Apparatus with function of detecting position of existence of metal body

ABSTRACT

The present invention consists of an apparatus comprising signal sending lines, each of which has a folded-back shape and serves to send a current for generating a magnetic field, and signal receiving lines, each of which has a folded-back shape, and which are arranged at a position permitting them to be electromagnetically coupled with the signal sending lines thus serving to detect a magnetic flux change caused by the approach of metal. The plurality of signal sending lines are arranged coplanarly, while the plurality of signal receiving lines are arranged coplanarly. The signal sending lines and the signal receiving lines are arranged with their planes held in parallel and in directions intersecting to each other, thereby constructing a sensing matrix. This sensing matrix is arranged in opposition to a panel along which a metal body to be detected moves, while holding there-between a space which is, at least, large enough to pass the metal body. The signal sending means and signal receiving means are connected to the sensing matrix so as to detect the location of the metal body.

TECHNICAL FIELD

The present invention relates to an apparatus with the function ofdetecting the location of a metal body. More particularly, it relates toan apparatus which has the function of detecting the location of a metalbody within, for example, a space held between parallel planes.

BACKGROUND ART

Apparatuses which need to have the function of detecting the location ofa metal body are, for example, metal detectors and game machines. By wayof example, some of the game machines are such that a metal body, e.g.,a metal ball is moved within a specified space which has been set in thegame machine, and whether or not a prize is won is determined inaccordance with the movement of the ball. A typical example of such agame machine is, for example, a "pachinko" (Japanese upright pinball)game machine with which a game player causes a metal "pachinko" ball tomove down within a space held between parallel planes and provided witha large number of obstacles.

The "pachinko" game machine has a panel which defines the space formoving the "pachinko" ball, a glass plate which covers the panel at afixed interval therefrom, and a projectile mechanism which functions toproject the "pachinko" ball to the upper part of the panel. The"pachinko" game machine is so installed that the panel extendssubstantially in the vertical direction. The panel is formed with aplurality of safe, holes each of which serves to make a hit when the"pachinko" ball has been led thereinto and driven out of the panel, anda single out hole into which the "pachinko" balls having failed to enterthe safe holes are finally gathered to be driven out of the panel.Besides, a large number of pins (or nails) are planted on the panelsubstantially perpendicularly thereto in the state in which theyprotrude from the panel to a distance corresponding to the diameter ofeach "pachinko" ball, in order that the "pachinko" ball falling alongthe panel may frequently collide against the pins to have its movingdirection altered. The pins are arranged on the panel in a predetermineddistribution in which, while altering the moving direction of thecolliding "pachinko" ball, they lead this ball so as to proceed towardthe safe hole in some cases and to miss the safe hole in other cases.

Owing to the construction as stated above, the "pachinko" game machinescome to have individualities, such as a machine in which it is easy toregister hits and a machine in which it is difficult to resister hits,depending upon the slight differences of the respective machines in thearrangement and inclinations of the pins. Even identical machinesinvolve such differences as having safe holes with a high hit rate andsafe holes with a low hit rate. Moreover, the differences are among themachines are considerable.

In a game center or the like where the game machines of this type areinstalled in large numbers, knowledge of the individualities of therespective game machines is important for management regarding theprofit administration and customer administration of the game center. Byway of example, when many of the machines resister hits excessively, thegame center side suffers a loss, whereas when all the machines aredifficult to resister hits on, customers come disinterested, which isunfavorable to business. Accordingly, it is necessary to know theindividualities of the respective game machines which are installed inthe center.

For such a purpose, it is practised to detect the moving courses of the"pachinko" balls in the "pachinko" game machine. In the official gazetteof Japanese Patent Application Publication No. 3560/1989, for example,there is disclosed an apparatus equipped with an upper sheet and a lowersheet which have a pair of contacts. This technique senses the existenceof the "pachinko" ball in such a way that the "pachinko" ball gets onthe upper sheet and depresses it, whereby the pair of contacts come intotouch.

With the prior-art apparatus, however, since the sheets have the pairsof contacts, they are restricted in arrangement, and they can bearranged only along the passages of the "pachinko" balls. It istherefore impossible to detect the motions of the balls from theperspective of the whole panel. This results in a difficult problem ofdetecting, for example, how the balls enter the safe holes and the outhole.

In addition, since the detection is based on the physical touch of thepair of contacts, it can take place in some moving states of the ballthat the depression of the sheet becomes too weak to bring the pair ofcontacts into touch, so the motion of the ball is not detected. Besides,inferior touches can occur due to the wear, corrosion etc. of the pairof contacts. Further, the erroneous touch of the pair of contacts can beincurred by a vibration or the like or by chattering. For these reasons,the apparatus lacks reliability.

Another problem is that, since pressure applied by the ball is utilized,the motion of the ball is easily affected.

Such problems can be encountered, not only in the "pachinko" gamemachine, but also in different machines. It is accordingly desired toovercome these problems.

DISCLOSURE OF THE INVENTION

An object of the present invention is to provide an apparatus with thefunction of detecting the location of a metal body, according to whichany location of the metal body within a specified space can be detectedout of touch with the metal body and without employing contacts attendedwith a physical touch, whereby a detected result of high reliability isobtained.

In order to accomplish the object, according to one aspect of thepresent invention, there is provided an apparatus with a function ofdetecting a metal body, which consists of a sensor including a signalsending line which has a folded-back shape, and which serves to send acurrent for generating a magnetic field when energized. The apparatusalso comprises a signal receiving line which has a folded-back shape,which is arranged at a position permitting it to be electromagneticallycoupled with the signal sending line, and which serves to detect amagnetic flux change caused by the approach of metal. The signal sendingline and the signal receiving line are arranged with their planes heldin parallel.

The sensor is constructed as a sensing matrix in which the plurality ofsignal sending lines are arranged coplanarly, the plurality of signalreceiving lines are arranged coplanarly, and the signal sending linesand the signal receiving lines are arranged with their planes held inparallel and in directions intersecting to each other.

The apparatus can further comprise signal sending means connected to therespective signal sending lines, for successively sending signals ofpredetermined frequency to the respective signal sending lines, andsignal receiving means connected to the respective signal receivinglines, for successively receiving the signals from the respective signalreceiving lines in synchronism with said signal sending means.

The signal sending means includes sending-signal switching means forsuccessively delivering signals-to-be-sent to the respective signalsending lines.

The signal receiving means includes receiving-signal switching means forsuccessively accepting signals-to-be-received from the respective signalreceiving lines.

The signal receiving means also includes decision means for judgingwhether or not the metal exists, from the signals of the signalreceiving lines and detection means for detecting induced currentsdeveloped in signal receiving lines, in a state in which the signalreceiving lines are isolated.

The detection means is characterized by being current transformers.

The signal receiving means can further include a signal processingcircuit for rectifying and smoothing the received signals, at a stagepreceding the decision means.

The apparatus further comprises a panel along which the metal bodyto-be-detected moves, wherein the sensing matrix is arranged inopposition to the panel while holding therebetween a space which is, atleast, large enough to pass the metal body, and wherein the signalsending means and signal receiving means are connected to the sensingmatrix, thereby detecting the location of the metal body.

The apparatus further comprises address generation means for evaluatingan address which indicates a position of the sensing matrix on the basisof the sending-signal switching means and the receiving-signal switchingmeans.

The apparatus further comprises record means for recording the addressof that position of the sensing matrix at which the metal body exists.

The apparatus further comprises monitor-position record means forrecording at least one specified position to-be-monitored on the panel,on the basis of the address of the sensing matrix.

The apparatus further comprises data processing means for comparingpositional information on the metal body detected in the sensing matrixand positional information of the monitor-position record means, therebyjudging whether or not the metal body has reached the specified monitorposition on the panel.

The apparatus further comprises write means for writing specifiedpositional information on the matrix, into the monitor-position recordmeans.

The apparatus comprises write means for writing specified positionalinformation on the matrix, into the monitor-position record means,wherein the monitor-position record means is detachable storage means.

The apparatus further comprises noise detection means for detectingnoise of the signal received by the signal receiving means, to deliver anoise detection signal as an output, and sending interrupt means forstopping the signal sending operation of the signal sending means inaccordance with the noise signal from the noise detection means.

The apparatus further comprises noise level measurement means formeasuring a level of the detected noise at each frequency, and frequencyswitching means for changing-over the frequency of the signal to-be-sentof the signal sending means to a frequency not affected by the detectednoise, on the basis of a measured result of the noise level detectionmeans.

The apparatus further comprises a band-pass filter by which thefrequency of the signal to-be-sent of the, signal sending means and thefrequency not affected by the detected noise are passed in the signalsending operation.

The apparatus comprises a person sensor which is located in front of thepanel so as to sense whether or not there is a person present.

In addition, according to the present invention, there is provided anapparatus further comprising a panel along which the metal body which isto be detected moves, wherein the sensing matrix is arranged inopposition to the panel while holding therebetween a space which is, atleast, large enough to pass the metal body, and wherein the signalsending means and signal receiving means are connected to the sensingmatrix, making it possible to detect the location of the metal body.

The panel is formed with a plurality of safe holes each of which servesto make a hit when said metal body has entered the hole and is so drivenout of the panel, and a single out hole into which the metal bodieshaving failed to enter any safe holes are finally gathered and drivenout of the panel. Also, a plurality of pins are planted on the panelsubstantially perpendicularly thereto in a state in which they protrudefrom the panel to a distance corresponding to a diameter of the metalbody, in order that said metal body falling along the panel mayfrequently collide against the pins to have its moving directionaltered. Further, the apparatus can comprise a projectile mechanism forprojecting the metal body to an upper part of the panel.

The pins have their distribution determined and are arranged on thepanel so that, while altering the moving direction of the collidingmetal body, they may lead the metal body so as to proceed toward safeholes in some cases and so as to miss safe holes in other cases.

A metal ball is employed as the metal body, whereby the apparatus can beused as a game machine.

When the magnetic field is generated by causing the current to flowthrough the signal sending line in the folded-back shape, an inducedcurrent is produced by the electromagnetic induction in the signalreceiving line near the signal sending line. On this occasion, when themetal body approaches the signal sending line and the signal receivingline, an eddy current is produced in the surface of the metal body inthe direction of canceling the magnetic flux based on the signal sendingline. Therefore, the magnitude of the induced current produced in thesignal receiving line changes under the influence of the eddy current.The approach of the metal body can be sensed by detecting the change.

In the case where the plurality of signal sending lines and signalreceiving lines are comprised and are arranged in the intersectingdirections so as to construct the sensing matrix, the signal sendingline and the signal receiving line whose electromagnetic characteristicshave changed with the approach of the metal body are detected, and theposition of the metal body in the sensing matrix can be grasped ascoordinates from the intersecting position of the detected signalsending and receiving lines. These signal sending and receiving linescan be specified by sensing the signal sending line which is driven byscanning, and the signal receiving line whose signal reception isselected by scanning.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic front view showing the configuration of a sensingmatrix for use in the first embodiment of the present invention.

FIG. 2 is a perspective view showing a game machine and the sensingmatrix which are conceptually disintegrated.

FIG. 3 is a vertical sectional view of a part of the game machine.

FIG. 4 is a front view of the sensing matrix.

FIG. 5 is an enlarged sectional view of an example of a signal sendingline or a signal receiving line for use in the present invention.

FIG. 6 is a block diagram showing the game machine side part of anexample of a signal processing system for use in the present invention.

FIG. 7 is a block diagram showing the main control device side of theexample of the signal processing system for use in the presentinvention.

FIG. 8 is a schematic waveform diagram showing the waveform of a voltagewhich is applied to the signal sending line.

FIG. 9 is a schematic front view showing the shape of a signal sendingline or a signal receiving line in the second embodiment.

FIG. 10 is a schematic front view showing the shape of a signal sendingline or a signal receiving line in the third embodiment.

FIG. 11 is a schematic front view showing the shape of a signal sendingline or a signal receiving line in the fourth embodiment.

FIG. 12 is a schematic front view showing the configuration of a sensingmatrix in the fifth embodiment.

FIG. 13 is a schematic front view showing the configuration of a sensingmatrix in the sixth embodiment.

FIG. 14 is a schematic front view showing the configuration of a sensingmatrix in the seventh embodiment.

FIG. 15 is an enlarged sectional view of an inner glass element whichincludes a sensing matrix in the eighth embodiment.

FIG. 16 is an enlarged sectional view of a signal sending line or asignal receiving line in the ninth embodiment.

FIG. 17 is a perspective view of a gaming slot machine in the tenthembodiment.

FIG. 18 is a front view of a sensing matrix in the eleventh embodimentof the present invention.

FIGS. 19A, 19B and 19C are enlarged sectional views of an inner glasselement which includes the sensing matrix.

FIG. 20 is an explanatory diagram showing an example of the detailedlayout of signal sending lines.

FIG. 21 is an enlarged sectional view of the signal sending line showingthe connected state of wire.

FIG. 22 is an enlarged front view of signal sending terminals.

FIG. 23 is a perspective view showing the state in which the inner glasselement is connected to a signal sending connector and a signalreceiving connector.

FIG. 24 is a general block diagram of a metal detection apparatus.

FIG. 25 is a block diagram of a signal sending circuit in a matrix I/Osending/receiving board.

FIG. 26 is a block diagram showing the principal part of a channelswitching logic.

FIG. 27 is a block diagram of a signal receiving circuit in the matrixI/O sending/receiving board.

FIG. 28 is a block diagram of signal receiving and signal sendingcircuits in a CPU memory control board.

FIG. 29 is a flow chart of the scanning of the sensing matrix.

FIGS. 30A, 30B, 30C and 30D are waveform diagrams showing the signalprocessing of a received signal.

FIG. 31 is a perspective view showing the state in which an inner glasselement in the twelfth embodiment of the present invention is connectedto a signal sending connector and a signal receiving connector.

FIG. 32 is a partial enlarged perspective view of signal sendingterminals or signal receiving terminals.

FIG. 33 is a side view showing the state in which the inner glasselement is connected to the signal sending connector and the signalreceiving connector.

FIG. 34 is an enlarged sectional view of an inner glass element whichincludes a sensing matrix in the thirteenth embodiment.

FIG. 35 is a schematic front view of a circumventing circuit board inthe fourteenth embodiment.

FIG. 36 is a block diagram showing the construction of noise reductionmeans.

FIG. 37 is a circuit diagram showing another example of theamplification means of a signal receiving circuit.

FIGS. 38a and 38b show waveform diagrams for explaining sampling points.

FIGS. 39a and 39b show waveform diagrams for explaining a peak holdingoperation.

FIGS. 40a and 40b show waveform diagrams in the case where noise iscontained in a signal.

FIG. 41 is an arrangement diagram showing an example of arrangement of aband-pass filter.

FIG. 42 is an explanatory diagram for elucidating a frequency band.

FIG. 43 is a block diagram showing the setup of a game player sensor inthe seventeenth embodiment.

FIG. 44 is a front view of an island showing the installation positionof a game player sensor in the eighteenth embodiment.

FIG. 45 is a perspective view showing the installation position of thegame player sensor in the seventeenth embodiment.

BEST MODES FOR CARRYING OUT THE INVENTION

Now, various embodiments of the present invention will be described withreference to the drawings.

FIGS. 1-8 show the first embodiment of the present invention. The firstembodiment illustrates a case where a metal detection apparatus isconstructed using a metal sensor and where it is applied to a gamemachine 10.

As shown in FIGS. 2 and 3, the game machine 10 includes a panel 11 whichdefines a space for moving a metal ball B, a glass cover 10a whichcovers the panel 11 with a fixed interval held therebetween, and aprojectile mechanism which serves to project the metal ball B toward theupper part of the panel 11. This game machine 10 is so installed thatthe panel 11 extends substantially in the vertical direction.

A guide rail 12 for defining a game region is mounted on the panel 11 ofthe game machine 10. A domain inside the guide rail 12 is the gameregion. A large number of pins (or nails) 13, 13, . . . for repellingthe metal ball B are planted and erected on the part of the panel 11within the game region. In addition, a plurality of `safe` holes 14a,14a, . . . are provided in various places, and a single `out` hole 15 isprovided at the lower end of the game region.

As depicted in FIG. 3, the pins 13 are erected to be substantiallyperpendicular in the state in which each pin protrudes from the panel 11by a length corresponding to the diameter of the metal ball B. Besides,the pins 13 are arranged so that the metal ball which falls along thepanel 11 while passing between the pins 13, 13 may frequently collideagainst the large number of pins 13 existent in its traveling course,thereby having its direction of movement changed. More specifically, asdepicted in FIG. 2, at least two of the pins 13 gather to form a pinline or pin group 13a. Such pin lines or pin groups 13a have theirdistribution determined in such a manner that, while having itsdirection of movement altered, the colliding metal body may be led so asto proceed toward the safe hole 14a in some cases or to miss the safehole 14a in other cases, depending upon the projected position of themetal body, namely, the fall starting point thereof, the movingdirection and speed thereof on that occasion, and so on.

The safe hole 14a is a hole which serves to make a hit when the metalbody enters it and is driven out of the panel 11. On the other hand, theout hole 15a is a hole into which the metal bodies having failed toenter any of the safe holes 14a are finally collected to be driven outof the panel 11.

The front glass cover 10a covering the panel 11 has a double structurecomposed of a front glass element 16 and an inner glass element 17.

The projectile mechanism includes a striking handle 18, and a drivemechanism not shown. The handle 18 is mounted at the front of the gamemachine 10, and is used for the operation of striking or knocking themetal body. The striking operation is effected by rotating the handle 18a desired angle.

Also, a ball dish 19 for receiving the metal bodies delivered by thegame machine 10 is mounted at the front of this game machine. Apredetermined number of metal bodies are awarded as a prize when themetal body projected to the panel 11 has entered any of the safe holes14a.

As shown in FIGS. 2 and 3, a sensing matrix 20 constituting the metalsensor is arranged extending along the panel 11 of the game machine 10.Of the front glass element 16 and the inner glass element 17constituting the front glass cover 10a for covering the panel 11, thelatter 17 which lies inwards as viewed from the game machine 10, namely,nearer the panel 11 is provided with the sensing matrix 20.

The inner glass element 17 is constructed by stacking three layers; aninner protective glass plate 17a which is a protective sheet for signalreceiving lines 26, a glass base plate 17b, and an outer glass plate 17cwhich is a protective sheet for signal sending lines 22. The signalreceiving lines 26 to be described later are laid in such a manner as tobe sandwiched in between the inner protective glass plate 17a and theglass base plate 17b. The signal sending lines 22 to be described laterare laid in such a manner as to be sandwiched in between the glass baseplate 17b and the outer glass plate 17c.

The whole front surface of the outer glass plate 17c lying in front ofthe plurality of signal sending lines 22 is formed with a shieldingtransparent conductor film 28. The transparent conductor film 28 is madeof, for example, an indium-tin oxide (I.T.O.) film or a tin oxide film.

As illustrated in FIG. 1, each of the signal sending lines 22 is laid ina folded-back shape (or a loop shape) having a paralleled portion 22P inwhich an outward path and a return path run in parallel, and a turningportion 22T in which the outward path is turned back to the return path.Also, each of the signal receiving lines 26 is laid in a folded-backshape (or a loop shape) having a paralleled portion 26P in which anoutward path and a return path run in parallel, and a turning portion26T in which the outward path is turned back to the return path. Theplurality signal sending lines 22 are arranged on the glass base plate17b so that their paralleled portions 22P may be arrayed within anidentical plane and may extend in parallel to one another. Likewise, theplurality of signal receiving lines 26 are arranged on the glass baseplate 17b so that their paralleled portions 26P may be arrayed within anidentical plane and may extend in parallel to one another. Besides, thesignal sending lines 22 and the signal receiving lines 26 are laid outso as to intersect to each other with, for example, the former lines 22juxtaposed in a column direction and the latter lines 26 juxtaposed in arow direction, thereby constructing the sensing matrix.

As shown in FIG. 5, the signal sending line 22 is manufactured in such away that a metal such as aluminum 22a is evaporated onto one surface ofthe glass base plate 17b, thereby forming the folded-back pattern ofthis signal sending line, and that the evaporated part is plated with ametal such as copper 22b along the pattern, thereby forming a metalplating pattern. The signal receiving line 26 is similarly manufacturedin such a way that aluminum is evaporated onto the other surface of theglass base plate 17b, thereby forming the folded-back pattern of thissignal receiving line, and that the evaporated part is plated withcopper.

The reaction sensitivity of at least either of the signal sending line22 and the signal receiving line 26 can be controlled by changing thethickness of the copper plating film. By way of example, when the copperplating is thickened, the D.C. resistance of the signal sending line 22or the signal receiving line 26 decreases to heighten the reactionsensitivity thereof to the metal body.

The inner glass element 17 is so fabricated that the inner protectiveglass plate 17a and the outer glass plate 17c are respectively joined onthe surface of the glass base plate 17b bearing the signal receivinglines 26 and on the surface thereof bearing the signal sending lines 22,with layers of a transparent adhesive.

As illustrated in FIG. 1, each of the signal sending lines 22 isU-turned into the folded-back shape of the parallel paths, and theplurality of signal sending lines 22 are arranged on the identical planewhile extending in parallel unidirectionally. Likewise, each of thesignal receiving lines 26 is U-turned into the folded-back shape of theparallel paths, and the plurality of signal receiving lines 26 arearranged on an identical plane while extending in parallelunidirectionally.

Each of the signal receiving lines 26 is arranged near the signalsending lines 22 so as to be electromagnetically coupled with theselines 22. More specifically, the signal receiving lines 26 are laid inthe direction of intersecting orthogonally to the signal sending lines22 at a position where their plane is parallel to the plane of thesignal sending lines 22 (that is, where the plane containing the signalsending lines 22 in the folded-back shape and the plane containing thesignal receiving lines 26 in the folded-back shape are arranged inparallel), in order that the electromagnetic characteristics of thelines 22 and 26 may be changed by the approach of metal such as themetal body B.

In the front view of FIG. 1, individual square parts enclosed with theintersecting signal sending lines 22 and signal receiving lines 26 formsensing units 20a, 20a, . . . each of which senses the metal body on thebasis of the change of an impedance being an electromagneticcharacteristic value.

Terminals 23 and 27 for external connections are respectively providedat the end parts of the plurality of signal sending lines 22 and theplurality of signal receiving lines 26. Besides, as shown in FIG. 4,some of the sensing units 20a, 20a, . . . correspond to the positions ofexistence of the safe holes 14a, 14a, . . . .

The pattern shapes of the signal sending line 22 and signal receivingline 26 are delicate in relation to the size of the metal body B. Whenthe sensing units 20a, 20a, . . . are too large, the resolving power ofthe metal sensor is inferior. When they are too small, the scanning rateof the metal sensor needs to be raised instead of an enhanced resolvingpower which permits an accurate pattern recognition.

Therefore, the D.C. resistances of the signal sending line 22 and signalreceiving line 26 are set preferably at 10 Ω to 200 Ω inclusive and mostpreferably at about 25 Ω, as the best value of the reaction sensitivityto the metal body B.

In addition, as indicated in FIG. 1, the turning-back width a of boththe signal sending lines 22 and signal receiving lines 26 is setpreferably between 4 mm and 16 mm inclusive and most preferably at 8 mm,as a value affording a good reaction sensitivity for sensing the metalbody B. Besides, regarding the spacing b between the adjacent signalsending lines 22 or signal receiving lines 26, a value in the order of0.5-2 mm exhibits a favorable result.

The pattern of the sensing matrix 20 suitable for the ordinary gamemachine 10 is one in which the signal sending lines 22 are in 32 rows,while the signal receiving lines 26 are in 32 columns, so that there area total number 1024 sensing units 20a.

Moreover, the diameter of the conductor of which each of the signalsending lines 22 and signal receiving lines 26 is made affects thesensitivity greatly. More specifically, when the diameter of theconductor is small, the impedance thereof becomes too high. When thediameter is large, the sensitivity worsens because the inside diameterof the pattern becomes small.

Further, since the sensing matrix 20 is disposed within the inner glasselement 17 covering the panel 11, the conductor needs to be fined to theutmost so as to prevent this sensing matrix from offending the eye whenplaying the game. Therefore, the diameter of the conductor to form eachof the signal sending lines 22 and signal receiving lines 26 ispreferably set at a value of 20 μm to 50 μm inclusive.

A signal processing system which constitutes the metal detectionapparatus for sensing the metal body, is as shown in FIGS. 6 and 7.

The system is operated under the control of a main control device 30. Asillustrated in FIG. 7, it includes the main control device 30; a logiccontroller 31 by which control signals etc. from the main control device30 are relayed; an impedance matching driver 32, a D.C. offsetcompensator 33, a hold circuit 34 and an A/D converter 35 whichconstitute an output loop from the sensing matrix 20 to the main controldevice 30; a timing generator 36; a power source unit 37; and anexternal connector 38. The logic controller 31 and the output loop areconnected to the external connector 38. The main control device 30 isconstructed of a computer including a central processing unit and a mainmemory though these are not shown.

On the side of the game machine 10, there are provided an output section40 which feeds power to the plurality of signal sending lines 22 of thesensing matrix 20, and an input section 50 which receives signals fromthe plurality of signal receiving lines 26. The output section 40 isdisposed to the side of the plurality of signal sending lines 22. Asshown in FIG. 6, the output section 40 includes a signal sending driver41 which applies signals to the signal sending lines 22, 22, . . .sequentially at predetermined cycles, and a decoder 42 which isconnected to the signal sending driver 41 and which controls the signalsending driver 41 so as to operate sequentially in accordance with thecontrol signals generated by the main control device 30. As shown inFIG. 8 by way of example, a continuous sinusoidal wave having afrequency of 1 [MHz] and centering at 0 [V] is suitable as a voltagewaveform 81 which is applied to the signal sending lines 22.

Further, a logic sequencer 43, a timing generator 44 and asignal-sending-line row counter 45 are included in the output section40.

The logic sequencer 43 operates in accordance with the control signalsfrom the main control device 30, and synchronizes the decoder 42 of thesignal sending side with a multiplexer 52 of the signal receiving sideto be described below. Simultaneously, it controls the timings of thestarts and ends of the cycles of the scanning of the sequential signalsof the decoder 42.

The timing generator 44 determines the cycles of the scanning. Herein,the frequency of the scanning needs to be at least 10 kHz for thepurpose of coping with the motions of the metal body on the panel 11 ofthe game machine 10, and it is set at 100 kHz in the embodiment. Thesignal-sending-line row counter 45 counts the scanning cycles, anddetermines the signal sending line 22 to be scanned.

The input section 50 is disposed to the side of the plurality of signalreceiving lines 26. It includes a converter 51 which is connected to theplurality of signal receiving lines 26 and which receives currentsexpressive of the electromagnetic characteristic values of theindividual signal receiving lines 26, 26, . . . and converts them intovoltage signals which are compatible with digital equipment atsucceeding stages; and the multiplexer 52 which is connected to theconverter 51 and which receives and delivers the signals from theindividual signal receiving lines 26, 26, . . . in sequence.

Connected to the multiplexer 52 is a signal-receiving-line columncounter 53 which is disposed at a stage succeeding the logic sequencer43 of the output section 40. The output section 40 and the input section50 are synchronized by the signal-sending-line row counter 45 and thesignal-receiving-line column counter 53 which are connected to the logicsequencer 43. As the aspect of the synchronization, by way of example,one of the plurality of signal receiving lines 26, 26 is subjected tothe signal detection every scanning operation of the plurality of signalsending lines 22, 22.

Alternatively, contrary to the above aspect of the synchronization, thesignal receiving lines 26, 26, . . . may be scanned once for thedetection every signal sending operation of one of the plurality ofsignal sending lines 22.

The output of the multiplexer 52 of the input section 50 is connected tothe external connector 38 via an impedance compensator 54.

Next, the operation of this embodiment will be described.

Referring to FIG. 7, when the address signals and the control signalsare respectively output from the main control device 30 to the logiccontroller 31 through an address bus and a control bus, they aretransmitted to the game machine 10 via the external connector 38.

Referring to FIG. 6, in the game machine 10, the logic sequencer 43 ofthe output section 40 produces a sequence signal on the basis of theentered signals. The sequence signal is delivered to the decoder 42, thetiming generator 44, and the signal-sending-line row counter 45 as wellas the signal-receiving-line column counter 53.

The timing generator 44 determines the cycles at which each signalsending line 22 of the sensing matrix 20 is scanned. Thesignal-sending-line row counter 45 counts scanning cycle signals, anddetermines the signal sending line 22 to be driven. This counter 45 isoperated in synchronism with the sequence signal from the logicsequencer 43.

The decoder 42 controls the signal sending driver 41 so as to operate insequence. Thus, the signal sending driver 41 delivers signals to thesignal sending lines 22, 22, . . . sequentially at the predeterminedcycles.

On the side of the plurality of signal receiving lines 26, the converter51 which has received the current signals expressive of theelectromagnetic characteristic values appearing at the plurality ofsignal receiving lines 26, 26, . . . converts these current signals intothe voltage signals which the digital circuits at the succeeding stagescan handle.

The multiplexer 52 which has received the converted signals affordedfrom the individual signal receiving lines 26, 26, . . . delivers themsequentially at predetermined cycles. The decoder 42 on the signalsending side and the multiplexer 52 on the signal receiving side aresynchronously operated by the count operations of thesignal-sending-line row counter 45 and the signal-receiving-line columncounter 53 which are in turn operated by the control signals of thelogic sequencer 43 having its operation based on the control signals.

The logic sequencer 43 causes the converter 51 and multiplexer 52 on thesignal receiving side to detect the information of one of the pluralityof signal receiving lines 26 every scanning operation of the pluralityof signal sending lines 22, or conversely to detect information itemsproduced by scanning the plurality of signal receiving lines 26 onceevery signal sending operation of one of the plurality of signal sendinglines 22.

When the voltage signal in the waveform as shown in FIG. 8 is applied toa certain one of the signal sending lines 22, an alternating magneticfield is generated in the paralleled portion 22P of the signal sendingline. Thus, the signal receiving lines 26 intersecting with this signalsending line 22 fall into the states in which alternating voltages areinduced by the electro-magnetic induction, respectively. On thisoccasion, when the metal body has entered a space which any of thesensing units 20a belonging to the signal sending line 22 views, an eddycurrent is induced in the metal body. The eddy current generates amagnetic field in the sense of canceling a magnetic flux produced fromthe paralleled portion 22P. Consequently, the magnitude of the magneticinduction in the intersecting signal receiving line 26 changes in thesensing unit 20a, and the current induced in the signal receiving line26 diminishes. In contrast, regarding the other signal receiving lines26 which intersect with the identical signal sending line 22, such achange does not take place, and hence, the induced currents do notchange. The particular signal receiving line 26 having its paralleledportion 26P at the position where the metal body exists, can be found byscanning the signal receiving lines 26, 26, . . . by the analogmultiplexer 52 to measure or compare the output values thereof, and thecolumn of the signal receiving line 26 whose output differs from theothers is checked for. Also, the particular signal sending line 22driven at that time can be found by checking the row thereof by way ofexample. Accordingly, the sensing unit 20a where the metal body existscan be known from the information items of both the lines.

Incidentally, by way of example, the signal sending line 22 which isdriven and the signal receiving line 26 which is selected by the analogmultiplexer 52 can be respectively known by obtaining the count value ofthe signal-sending-line row counter 45 and by obtaining the count valueof the signal-receiving-line column counter 53. The position of themetal body can be grasped from the row of the signal sending line andthe column of the signal receiving line, as the coordinates of theposition where these lines intersect.

There are a total number of 1024 sensing units 20a which are incorrespondence with the 32 rows of the signal sending lines 22 and the32 columns of the signal receiving lines 26. Therefore, no matter whichof the safe holes 14a and the out hole 15 in the panel 11 the metal bodymay pass through, it can be .detected.

Incidentally, since the voltage waveform 81 for the signal sending lines22 is the continuous sinusoidal wave centering at 0 [V], noise as in thecase of a square wave does not develop, and detrimental effects on theother devices such as the main control device 30 can be prevented.

Each of the sensor signals delivered from the multiplexer 52 issubjected to impedance compensation by the impedance compensator 54.Subsequently, the sensor signal delivered from the impedance compensator54 enters the impedance matching driver 32 on the side of the maincontrol device 30 via the external connector 38 and is subjected toimpedance matching therein. The D.C. offset compensator 33 succeedingthe impedance matching driver 32 receives only the reaction wave of theoutput from the sensing matrix 20 and delivers it to the hold circuit34.

In the hold circuit 34, the data transmitted at high speed istemporarily held and stored until the end of the A/D conversionoperation being carried out in the succeeding A/D converter 35. In theA/D converter 35, the analog signal from the sensing matrix 20 isconverted into a digital signal containing a predetermined number ofbits, for example, a 12-bit unit, so as to transmit the digital data tothe main control device 30 via a data bus. The operations of the holdcircuit 34 and A/D converter 35 are synchronized by the signal of thelogic controller 31 or timing generator 36.

The motions of all the metal bodies on the sensing matrix 20 may well bestored for a long time in such a way that an output terminal isseparately prepared for the A/D converter 35 and is connected to anunshown memory device.

Incidentally, since the signal sending lines 22 and the signal receivinglines 26 are folded back in the U-turns into the paralleled portions andare intersected orthogonally to each other, the sensing matrix 20 has asimple pattern which is inoffensive to the eye and can be readilyfabricated of a wire material such as copper wire. Moreover, since thesignal sending lines 22 and the signal receiving lines 26 of the sensingmatrix 20 have smaller lengths and lower D.C. resistances than if theyhad bent position, a good reaction sensitivity is attained.

In addition, the transparent conductor film 28 on the front surface ofthe outer glass plate 17c functions to shield the sensing matrix fromthe disturbing electrical influences of metals and dielectrics and alsoto raise the reaction sensitivity to the metal body.

The positions of the sensing units 20a, 20a, . . . corresponding to thesafe holes 14a, 14a, . . . are stored, together with the position of theout hole 15 (the number of "hit" balls can be known when the number ofthe metal bodies projected and struck onto the panel 11 is countedwithout detecting the metal bodies in the out hole 15), whereupon thesituation in which the metal bodies enter the individual holes ismonitored with the progress of the game. Depending upon circumstances,the last strike (the end of the game) is managed, and any abnormalityascribable to an unfair practice is checked. Besides, data to beutilized for, e.g., adjusting the amount of direction change exerted onthe metal bodies by the pins can be collected by finding the machine inwhich the metal bodies find it extraordinarily easy to enter only aspecified one of the safe holes, the machine in which the metal bodiesfind it extraordinarily difficult to enter the safe holes, and so forth.

The second embodiment of the present invention is described below.

FIG. 9 shows the shape of a signal sending line or a signal receivingline in the second embodiment. The signal sending line (or signalreceiving line) 222 is bent in a zigzag fashion. Except for thedifferent shape, this embodiment is the same as the first embodiment.

Now, the third embodiment of the present invention will be described.

FIG. 10 shows the shape of a signal sending line or a signal receivingline in the third embodiment. The signal sending line (or signalreceiving line) 322 has the shape in which the portion of a sensing unit20b is expanded to be circular. Also this embodiment is the same as thefirst embodiment except for the different shape.

The fourth embodiment of the present invention is described below.

FIG. 11 shows the shape of a signal sending line or a signal receivingline in the fourth embodiment. The signal sending line (or signalreceiving line) 422 is in the zigzag shape in which the portion of asensing unit 20c is expanded to be square, and such lines have a layoutin which the zigzag patterns of the adjacent signal sending lines orsignal receiving lines are interlocked. Also this embodiment is the sameas the first embodiment except for the different shape.

As exemplified by the second embodiment, third embodiment and fourthembodiment, the signal sending lines or signal receiving lines can havevarious shapes in accordance with applications, purposes in use, etc.Besides, the signal sending line and the signal receiving line need notbe in the same line shape, but they may well have different line shapesin combination.

The fifth embodiment of the present invention is described below.

FIG. 12 shows the shape of a sensing matrix in the fifth embodiment. Thesensing matrix 520 is so configured that a plurality of signal sendinglines 522 and a plurality of signal receiving lines 526 are ledunidirectionally (upwards in FIG. 12) and are curved 45 degrees so as toextend in directions intersecting to each other, thereby being laid outin the directions intersecting orthogonally to each other. Also thisembodiment is the same as the first embodiment except for the differentconfiguration.

In this embodiment, as illustrated in FIG. 12, an area 526A and an area522B are designed so as to keep a substantially constant pattern length.Therefore, the difference between the total length of the plurality ofsignal sending lines 522 and that of the plurality of signal receivinglines 526 decreases. As compared with those of the first embodiment,accordingly, the plurality of signal sending lines 522 and the pluralityof signal receiving lines 526 have substantially equal D.C. resistances,which can be easily uniformalized among the signal sending lines 522 andamong the signal receiving lines 526, with the result that the reactionsensitivity can be made uniform.

In the above example, the plurality of signal sending lines 522 and theplurality of signal receiving lines 526 have substantially equal D.C.resistances. The D.C. resistances of both the sorts of lines, however,may well differ depending upon the applications, the purposes in use,etc. The sixth embodiment and seventh embodiment of the presentinvention are such examples.

FIG. 13 shows the configuration of a sensing matrix in the sixthembodiment. This embodiment is the same as the first embodiment exceptfor the different configuration.

In this embodiment, pattern lengths in an area 122A and an area 126B arevery different. Further, in the area 126B, a line part 126a and a linepart 126b have unequal pattern lengths. Consequently, the plurality ofsignal sending lines 22 and the plurality of signal receiving lines 26have discrepancies in their D.C. resistances.

FIG. 14 shows the configuration of a sensing matrix in the seventhembodiment. Also this embodiment is the same as the first embodimentexcept for the different configuration.

Also in this embodiment, pattern lengths differ in an area 222A, an area226B and an area 227B, and the pattern lengths of a line part 227a and aline part 227b are unequal in the area 227B. Consequently, the pluralityof signal sending lines 22 and the plurality of signal receiving lines26 have discrepancies in their D.C. resistances.

In this manner, the sensing matrices can be endowed with variousconfigurations, depending upon the applications, the purposes in use,etc.

The eighth embodiment of the present invention is described below.

FIG. 15 shows the structure of an inner glass element including asensing matrix in the eighth embodiment. The inner glass element 817 isso constructed as to stack the four layers of an inner protective glassplate 817a, a signal receiving side glass base plate 817b, a signalsending side glass base plate 917b and an outer glass plate 817c. Aplurality of signal receiving lines 826 of paralleled folded-back shape,are formed on one surface of the signal receiving side glass base plate817b and have the inner protective glass plate 817a stuck thereon. Aplurality of signal sending lines 822 of paralleled folded-back shape,are formed on one surface of the signal sending side glass base plate917b and have the outer glass plate 817c stuck thereon. In addition, theinner glass element 817 is fabricated in such a way that the base platesurface of the signal receiving side glass base plate 817b and the baseplate surface of the signal sending side glass base plate 917b are stucktogether with a transparent adhesive. The others are the same as in thefirst embodiment.

In this manner, the inner glass element 817 is fabricated by stickingthe two glass base plates 817b and 917b together, whereby thefabrication of this inner glass element 817 is facilitated.

Incidentally, in this embodiment, the two glass base plates 817b and917b may well be replaced with a single glass base plate, both thesurfaces of which are patterned to form the signal sending lines 822 ofthe folded-back shape and the signal receiving lines 826 of thefolded-back shape, respectively.

Alternatively, the patterning may well be performed on the surfaces ofthe inner protective glass plate 817a and the outer glass plate 817c.

Apart from glass, the base plates 817b and 917b may well be made ofplastics films.

The ninth embodiment of the present invention is described below.

FIG. 16 shows a signal sending line or a signal receiving line in theninth embodiment. The signal sending line 922 is manufactured in such away that a transparent conductor pattern made of an I. T. O. film 922ais formed on one surface of a glass base plate 117b, and that a filmmade of a metal 922b such as copper is formed on and along the patternby evaporation, plating or the like. The I. T. 0. film can be formed bya thin-film technique, for example, sputtering. The signal receivingline is similarly manufactured in such a way that a transparentconductor pattern made of an I. T. O. film is formed on the othersurface of the glass base plate 117b, and that a film of copper isformed on the pattern.

Even in a case where the copper pattern of the signal sending line 922or the signal receiving line has broken, the underlying transparentconductor pattern is kept connected, and hence, the disconnection of thepattern of the signal sending or receiving line can be prevented.

Incidentally, a copper foil may well be stuck with anelectrically-conductive adhesive instead of the formation of the copperfilm on the I. T. O. film.

Although each of the foregoing embodiments has referred to the gamemachine, the utilization of the sensing matrix is not restrictedthereto. The sensing matrix is capable of, for example, the detection ofthe distribution state of the metal bodies and the detection of themotions of the metal bodies. The utilization of the former makes itpossible by way of example to detect whether or not commodities are keptin stock, in such a way that a metal piece of specified pattern isaffixed to each of the commodities and that the commodities are arrangedin the configuration of the sensing matrix described before.Accordingly, this expedient is applicable to the stock management ofcommodities. It is also applicable to the management of the quantity ofarticles by affixing similar metal pieces to the articles. Besides, thesensing matrix can be applied to a sensing apparatus for performing thecount, check etc. of the metal bodies at a corner where these metalbodies are exchanged for game prizes.

The tenth embodiment of the present invention is described below.

FIG. 17 shows a gaming slot machine in the tenth embodiment. The slotmachine 101 is so constructed that the outer peripheral surfaces of sixrotators 111 bear a plurality of sorts of common displays 112. A gamingtoken is inserted into a medal inlet 121, and a handle 122 is pulledtoward this side, whereby a game is started in which the individualrotators 111 rotate at high speeds. Subsequently, stop buttons 123 aresuccessively depressed, whereby the rotators 111 corresponding to thebuttons are successively stopped.

Thus, any of the plurality of displays is brought to the position of adisplay window 113 in each of the rotators 111 every game. When all thedisplays 112 brought to the display windows 113 are predeterminedpremium-awarding displays, for example, the displays "7", a premium isdelivered to a premium outlet 125.

Here, each rotator 111 is formed of a belt or sheet made of anonconductor such as plastics or rubber, and it is rotated by two beltpulleys not shown. In each rotator 111, a metal such as iron (not shown)is attached to the position of the predetermined premium-awardingdisplay, for example, "7". The display window 113 is covered with afront glass cover 131. The front glass cover 131 has a structure similarto that of the inner glass element 17 in the first embodiment (refer toFIG. 3). The inner glass element 17 includes the sensing matrix 20constructing the metal sensor. Besides, the sensing matrix 20constitutes the metal detection apparatus for sensing the metal, in thesame manner as in the first embodiment. These, however, shall not beexplained further because the explanation is a repetition of that of thefirst embodiment.

When all the displays positioned to the display windows 113 are thepredetermined premium-awarding displays, for example, "7" when therotators 111 are stopped, the sensing matrix 20 senses this state. Thepositions of the metal sensed by the sensing matrix 20 are transmittedto a built-in CPU, for example, the CPU of the main control device 30 asshown in FIG. 3. Then, when the CPU has acknowledged the predeterminedpremium-awarding displays, the premium is delivered to the premiumoutlet 125.

Incidentally, the sensing matrix 20 may well be formed inside the gamingslot machine 101, not at the display windows 113 at the front of theslot machine 101. Besides, the positions of the metal may well bedetected by the built-in CPU after the start positions of the rotators111 have been acknowledged by the sensing matrix 20.

Also in this embodiment, as in the first embodiment, the front glasscover 131 may well be put into the double structure which is composed ofthe front glass element 16 and the inner glass element 17.

In each of the foregoing embodiments, the sensing matrix can constitutea touch sensor, or a metal pattern discrimination apparatus fordiscriminating the pattern of metal in, for example, a printed-wiringcircuit board.

Moreover, when the sensing matrix is set at an appropriate density, itis also capable of tracking the trajectory of the metal body, wherebythe game can also be monitored in detail. The sensing matrix may well bedisposed rearward of the panel of the game machine.

Incidentally, the sensing units 20a, 20a, . . . need not always besquare, but they may well have various appropriate shapes.

Apart from the copper, the conductor of which the signal sending lines22 and the signal receiving lines 26 are made may well be a metal suchas aluminum or gold, or a transparent conductor in the form of a film,such as indium oxide or tin oxide.

In addition, each of the foregoing embodiments has referred to the metalsensor in which the plurality of signal sending lines and signalreceiving lines constitute the sensing matrix. However, the plurality ofsignal sending lines or signal receiving lines are not always required,but the sensing matrix may well be formed of a simple configurationcomposed of a single signal sending line and a single signal receivingline.

The eleventh embodiment of the present invention is described below.

FIGS. 18-30 show the eleventh embodiment of the present invention.Likewise to the first embodiment, the eleventh embodiment illustrates acase where a metal detection apparatus is constructed using a metalsensor and is applied to a game machine.

As shown in FIG. 18, a single signal sending line 622 is U-turned at aturning portion 61 into a folded-back shape having a paralleled portion,and a plurality of such signal sending lines 622 are arranged on anidentical plane while extending in parallel unidirectionally. Likewise,a single signal receiving line 626 is U-turned into a folded-back shapehaving a paralleled portion, and a plurality of such signal receivinglines 626 are arranged on an identical plane while extending in parallelunidirectionally. That is, each of the signal sending lines 622 and thesignal receiving lines 626 includes the turning portion, and theparalleled portion in which an outward path and a return path are heldin parallel. Signal sending terminals 623 and signal receiving terminals627 are concentratedly arranged at a lower end in relation to an innerglass element (front glass) 617 which is attached to the game machine.

Each signal receiving line 626 is laid close enough to the individualsignal sending lines 622 to be electromagnetically coupled with them.The signal receiving lines 626 have their plane held in parallel withthe plane of the signal sending lines 622 and are extended in thedirection intersecting orthogonally to the extending direction of theselines 622 in order that their electromagnetic characteristics may bechanged by the approach of a metal body. The signal sending lines 622and the signal receiving lines 626 constitute a sensing matrix 620.

Likewise to the sensing matrix in the first embodiment, the sensingmatrix 620 shown in FIG. 18 is disposed along the panel of the gamemachine as shown in FIG. 2. In the front view of FIG. 18, portions ofregular square shape, which are respectively enclosed with the signalsending lines 622 and signal receiving lines 626 intersecting with eachother, define sensing units 620a, 620a, . . . each of which is formed soas to sense a magnetic flux generated by the signal sending line,through the signal receiving line and each of which detects a fluxchange induced by the metal body, thereby finding the existence of thismetal body. Some of the sensing units 620a, 620a, . . . correspond tothe safe holes 14a, 14a, . . . as shown in FIG. 4o The sensing matrix620 is provided in the inner glass element (front glass) 617 lyinginwards and nearer the panel, of two glass elements which cover thepanel as depicted in FIG. 19C.

FIG. 19C shows a partial sectional view of the game machine to whichthis embodiment is applied, FIG. 19A shows an enlarged sectional view ofthe inner glass element, and FIG. 19B shows an enlarged view of acircular part enclosed with a broken line in FIG. 19A. The inner glasselement 617 is constructed by stacking four layers; an inner protectiveglass plate 617a which is a protective sheet for the signal receivinglines 626 (shown in FIG. 18), a glass base plate 617b on a signalreceiving side, a glass base plate 617c on a signal sending side, and anouter glass plate 617d which is a protective sheet for the signalsending lines 622 (shown in FIG. 18). The inner protective glass plate617a and the outer glass plate 617d are vertically shorter than thesignal-receiving-side glass base plate 617b and the signal-sending-sideglass base plate 617c and as a result, the inner glass element 617 isexposed at its lower end 617p.

As illustrated in FIG. 19C, the plurality of signal receiving lines 626in the paralleled folded-back shape (shown in FIG. 18) are laid in amanner so as to be sandwiched in between the inner protective glassplate 617a and the signal-receiving-side glass base plate 617b. Theplurality of signal sending lines 622 in the paralleled folded-backshape (shown in FIG. 18) are laid in a manner so as to be sandwiched inbetween the signal-sending-side glass base plate 617c and the outerglass plate 617d. Accordingly, the inner glass element 617 is fabricatedin such a way that the signal sending lines 622 are laid on one surfaceof the signal-sending-side glass base plate 617c by sticking them with atrans-parent binder layer 618a, that the outer glass plate 617d is stuckon the signal sending lines with a trans-parent binder layer 618b, thatthe signal receiving lines 626 are laid on the other surface of thesignal-receiving-side glass base plate 617b by sticking them with atransparent binder layer 618c, that the inner protective glass plate617a is stuck on the signal receiving lines with a transparent binderlayer 618d, and that the other surface of the signal-sending-side glassbase plate 617c and the other surface of the signal-receiving-side glassbase plate 617b are stuck together by the use of a transparent binderlayer 618e.

A transparent conductor film 28 for shielding the sensing matrix isprovided on the entire front surface, of the outer glass plate 617dlying in front of the plurality of signal sending lines 622. Thistransparent conductor film is formed of any of an indium-tin oxide (I.T. O. ) film, a tin oxide film, etc.

As illustrated in FIG. 18, the signal-sending-side glass base plate 617cin a square shape has a signal-sending-side turning circuit board 619abonded thereto along one vertical latus thereof, the circuit board 619abeing formed of an elongate flexible printed-wiring circuit board (FPC),and it also has a signal-sending-side circumventing circuit board of anL shape 619b bonded thereto along the opposite vertical latus thereofand part of the bottom latus thereof, the circuit board 619b beingsimilarly formed of a flexible printed-wiring circuit board. Thesignal-sending-side turning circuit board 619a is such that, as shown inFIG. 20, a plurality of arcuate turning portions 61, specifically, 32 ofthem, are formed in a row by conductor patterns made of copper foil, andthat, as shown in FIG. 21, one end 62a of each piece of wire 62 isconnected to one end 61a of the corresponding turning portion 61 bywelding or soldering with solder 63.

As depicted in FIG. 18 and in FIG. 22 showing an enlarged view of acircular part enclosed with a broken line in FIG. 18, the signal sendingterminals 623 of which there are a plurality, specifically there are 64,and which extend vertically for external connections are formed ofconductor patterns made of copper foil, on the lower-end edge of thesignal-sending-side circumventing circuit board 619b opposite theturning circuit board and along part of the lower-end latus.

As shown in FIG. 19B, the signal sending terminals 623 are arranged atthe lower end 617p of the inner glass element 617 and are exposed due tothe fact that they are not concealed by the outer glass plate 617d. Thatis, the outer glass plate 617d is stuck on the surface part of thesignal-sending-side glass base plate 617c bearing the signal sendinglines 622, except the part thereof bearing the signal sending terminals623. On the terminal side of each of the signal sending lines 622, thereare the signal sending terminal 623 of the corresponding signal sendingline 622 and a circumventive portion 64 for this signal sending terminal623. The circumventive portions 64 for leading the signal sending linesto the signal sending terminals 623 are formed of conductor patterns onthe signal-sending-side circumventing circuit board 619b, and are laidalong this signal-sending-side circumventing circuit board 619b from thecorresponding signal sending terminals 623.

Referring to FIG. 20, while being tensed, the wire piece 62 extendingfrom the end 61a of each of the turning portions 61 has its other end62b connected to the start point 64a of the corresponding circumventiveportion 64 on the terminal side by welding or soldering with a solder63, whereupon the end 62b is connected to the signal sending terminal623 through the circumventive portion 64. Incidentally, regarding thecircumventive portions 64, two straight parts are connected using roundparts in order to eliminate any high-frequency problems.

Similarly, the signal-receiving-side glass base plate 617a in a squareshape has a signal-receiving-side turning circuit board 629a bondedthereto along one lateral top latus thereof, and it also has an elongatesignal-receiving-side circumventing circuit board 629b bonded theretoalong part of the lateral bottom latus thereof. Likewise to thesignal-sending-side turning circuit board 619a, thesignal-receiving-side turning circuit board 629a is such that aplurality of arcuate turning portions 61, specifically, 32 of them, areformed of conductor patterns made of copper foil, and that one end 62aof each piece of wire 62 is connected to one end 61a of thecorresponding turning portion by welding or soldering with solder 63.

The plurality of signal receiving terminals 627, specifically, 64 ofthem, which extend vertically for external connections are formed ofconductor patterns made of copper foil, on the lower-end edge of thesignal-receiving-side circumventing circuit board 629b opposite theturning circuit board and along part of the lower-end latus. Thesesignal receiving terminals are located at non-confronting positions atwhich they do not overlap the signal sending terminals when thesignal-receiving-side glass base plate 617b is stuck to thesignal-sending-side glass base plate 617c.

As shown in FIG. 19A, the signal receiving terminals 627 are arranged atthe lower end 617p of the inner glass element 617 and are exposed due tothe fact that they are concealed by the inner protective glass plate617a. That is, the inner protective glass plate 617a is stuck on thesurface part of the signal-receiving-side glass base plate 617b bearingthe signal receiving lines 626, except the part thereof bearing thesignal receiving terminals 627. On the terminal side of each of thesignal receiving lines 626, there are the signal receiving terminal 627of the corresponding signal receiving line 621 and a circumventiveportion 64 for this signal receiving terminal 627. The circumventiveportions 64 for leading the signal receiving lines to the signalreceiving terminals 627 are formed of conductor patterns on thesignal-receiving-side circumventing circuit board 629b, and are laidalong this signal-receiving-side circumventing circuit board 629b fromthe corresponding signal receiving terminals 627.

While being tensed, the wire piece 62 extending from the end 61a of eachof the turning portions 61 has its other end 62b connected to the startpoint 64a of the corresponding circumventive portion 64 on the terminalside by welding or soldering with solder 63, whereupon the end 62b isconnected to the signal receiving terminal 627 through the circumventiveportion 64.

In this manner, each of the signal sending lines 622 or the signalreceiving lines 626 is made up of the turning portion 61 which is formedon the corresponding turning circuit board 619a or 629a, thecircumventive portions 64 which are formed on the correspondingcircumventing circuit board 619b or 629b, the wire pieces 62, and thesignal sending terminal 623 which forms the end part of the signalsending line 622 or the signal receiving terminal 627 which forms theend part of the signal receiving line 626. Incidentally, the surface ofeach wire piece 62 has a delustered black color and prevents thereflection of light in order to be inoffensive to the game player's eye.

The pattern of the sensing matrix 620 suitable for the ordinary gamemachine 10 is one which has the signal sending lines 622 in 32 rows andthe signal receiving lines 626 in 32 columns, so that there are a totalof 1024 sensing units 620a. Incidentally, in FIG. 18, the pattern exceptthe outer part thereof is omitted from illustration.

The diameter of the wire of which each of the signal sending lines 622and signal receiving lines 626 is formed is preferably set at a value of25 μm-30 μm. In the case of this embodiment, the entire widths c and dof the signal sending terminals 623 and signal receiving terminals 627as indicated in FIG. 18 are respectively set at 126 mm, and the widths eand f of the vertically-extending parts of the signal-sending-sideturning circuit board 619a and signal-sending-side circumventing circuitboard 619b as indicated in FIG. 20 are respectively set at 10 mm orless.

Besides, the width g of each of the signal sending terminals 623 andsignal receiving terminals 627 as indicated in FIG. 22 is 1.5 mm. Owingto the fact that the widths e and f of the circumventive portions 64 areset at 10 mm or less, the signal-sending-side turning circuit board 619aand the signal-sending-side circumventing circuit board 619b are hiddenby a mounting frame for the inner glass element (front glass) 617 of thegame machine and cannot be seen from the front side where the gameplayer stands.

As shown in FIG. 23, a signal sending circuit board 66a and a signalreceiving circuit board 66b are installed at the inner lower part of themounting frame. The signal sending circuit board 66a is provided with asignal sending circuit 640 for sending signals to the plurality ofsignal sending lines 622 of the sensing matrix 620, while the signalreceiving circuit board 66b is provided with a signal receiving circuit650 for receiving signals from the plurality of signal receiving lines626. A signal sending connector 67a and a signal receiving connector 67bare respectively mounted on those positions of the circuit boards 66aand 66b which correspond to the signal sending terminals 623 and thesignal receiving terminals 627.

The signal sending connector 67a is an edge connector for detachablyconnecting the signal sending terminals 623 to the signal sendingcircuit 640 on the signal sending circuit board 66a, while the signalreceiving connector 67b is an edge connector for detachably connectingthe signal receiving terminals 627 to the signal receiving circuit 650on the signal receiving circuit board 66b. More specifically, the signalsending connector 67a or signal receiving connector 67b is soconstructed that the upper part of an elongate insulator member 68extending along the signal sending circuit board 66a or signal receivingcircuit board 66b is formed with a slit 68a in the lengthwise directionof the insulator member, and that a large number ofelectrically-conductive rubber pieces connecting to the correspondingcircuit board 66a or 66b are packed in the bottom of the slit 68a in adirection perpendicular to the circuit board 66a or 66b.

The inner glass element (front glass) 617 in which the signal sendingterminals 623 and the signal receiving terminals 627 are arranged, canbe inserted into the slits 68a of the insulator members 68. The signalsending connector 67a is connected with the signal sending terminals 623of the signal sending lines 622 in the state in which the inner glasselement 617 is held between both the inner surfaces of this connector,while the signal receiving connector 67b is connected with the signalreceiving terminals 627 of the signal receiving lines 626 in the samemanner.

The signal sending terminals 623 and signal receiving terminals 627 arerespectively connected with the signal sending circuit 640 and signalreceiving circuit 650 as follows: The signal sending terminals 623 andsignal receiving terminals 627 are positioned under the inner glasselement 617 and are inserted into the corresponding slits 68a so as tobe able to connect with the signal sending connector 67a and signalreceiving connector 67b, and the resulting inner glass element 617 isfitted in the mounting frame so that the signal sending terminals 623and signal receiving terminals 627 may be reliably connected with thesignal sending connector 67a and signal receiving connector 67b by theweight of the element 617 which is about 1.2 [kg].

A signal processing system which constitutes the metal detectionapparatus for sensing the metal body, is as shown in FIGS. 24-28.

As illustrated in FIG. 24, the sensing matrix 620 is under the controlof a CPU memory control board 72 through a matrix I/O sending/receivingboard 71. The CPU memory control board 72 constructs data processingmeans, and is capable of communication by means of a communicationcircuit 79. Besides, the CPU memory control board 72 includes aninterface portion 76 for reading positions to-be-monitored (monitorpoints) from a RAM card 73. This CPU memory control board 72 has acentral processing unit (CPU), a main memory, an interface functionunit, etc. packaged therein, whereby a computer is, in effect,constructed.

The RAM card 73 is storage means, and is a memory card which isdetachably set in the interface portion 76. It stores therein dataindicative of the monitor points for the metal body, and it allows thedata to be read therefrom and written thereinto. The monitor points arethe address data items which indicate the preset specific positions ofsafe holes 14a, 14a, . . . , a projected-ball detection position, and anout hole 15.

Besides the monitor points, the RAM card 73 stores therein an algorithmfor detecting the metal ball entering any of the safe holes 14a, 14a, .. . and out hole 15; etc. By way of example, it has a program which cancount the numbers of safe balls and out balls upon recognizing theentries of the metal bodies into the safe holes 14a, 14a, . . . and theout hole 15 when the detected positions of the metal bodies and themonitor points compared have agreed, and which is processed in the CPUmemory control board 72. Besides, a correspondence table may well beincluded in the CPU memory control board 72 for cases where the detectedpositions of the metal bodies and the monitor points do not correspond.The CPU memory control board 72 compares the detected positions of themetal bodies and monitor points by referring to the correspondence tablein the comparing operations.

The CPU memory control board 72 is also capable of recording the data ofthe positions or traces of the detected metal balls, in an option card74.

The option card 74 to be connected to the CPU memory control board 72 isa recorder which can be externally connected, and which records thetraces of the metal bodies that move about in the interspace between thepanel 11 and inner glass element 617 of the game machine 10. One aspectof the option card 74 is a system in which the data is stored in asemiconductor memory or the like. Besides, in a time zone in which thenumber of the game players increases, the activity rate of each gamemachine 10 heightens, and hence, an enormous storage capacity isrequired. In this regard, since the semiconductor memory requiring theenormous storage capacity is usually expensive or in need of a largerspace, the option card 74 may well record the motions of the metalbodies by the use of a hard disk. Apart from the hard disk, the optioncard 74 may well employ any of an optical disk, an analog or digitalrecording tape, a video tape, etc. In addition, a personal computer canbe directly connected to the option card 74.

The CPU memory control board 72 can display and print the trace of themetal body in such a way that the data recorded in the option card 74 isprocessed by the computer 75 prepared outside.

The recorded data is applied to, and arithmetically processed by, thecomputer in which the software for analyzing the traces of the metalbodies is set, whereby data needed in a game center or the like can beobtained.

The matrix I/O sending/receiving board 71 includes the signal sendingcircuit board 66a provided with the signal sending circuit 640, and thesignal receiving circuit board 66b provided with the signal receivingcircuit 650. The signal sending circuit 640 is a circuit which sendssignals of predetermined frequency to the individual signal sendinglines 622 sequentially while the signal receiving circuit 650 is acircuit which receives signals from the individual signal receivinglines 626 sequentially in synchronism with the signal sending circuit640.

As shown in FIG. 25, the signal sending circuit 640 is configured of asignal sending connector 641, an amplifier 642, channel switching logic643, an analog multiplexer 644, and a plurality of totem-pole drivers ofPNP and NPN transistors 645.

The totem-pole drivers 645, specifically, 32 of them, are respectivelyconnected to the sides of the signal sending lines 622 of 32 circuitchannels.

As shown in FIG. 26, the channel switching logic 643 is operated withtwo clocking and resetting control signals, by effectively utilizing acounter IC 643a. This channel switching logic 643 is signal-sendingswitching means, and it instructs the analog multiplexer 644 withaddresses corresponding to the channels of the signal sending lines 622,specifically, 32 circuit channels, to thereby sequentially change-overthe signal sending operations.

As shown in FIG. 27, the signal receiving circuit 650 is configured of aplurality of CT sensors (current transformers) 651, an analogmultiplexer 652, an amplifier 653, a channel switching logic 654, and asignal receiving connector 655, all of the above components beingconnected through the signal receiving connector 67b.

The CT sensors (current transformers) 651 specifically number 32, andare respectively connected to the sides of the signal receiving lines626 of 32 circuit channels.

Accordingly, the signal receiving circuit 650 is adapted to receivesignals from the respective signal receiving lines 626 through thecorresponding CT sensors 651. The channel switching logic 654 is thecomponent which is similar to the channel switching logic 643 of thesignal sending circuit 640.

Each of the CT sensors 651 isolates the corresponding signal receivingline 626 from the analog multiplexer 652, and amplifies the signal fromthe signal receiving line 626 by 10 times.

The analog multiplexer 652 accepts the signals from the individual CTsensors 651 sequentially, and the amplifier 653 amplifies each of thesignals from the analog multiplexer 652. The channel switching logic 654is signal-receiving switching means. Likewise to the channel switchinglogic 643 of the signal sending circuit 640, the logic 654 instructs theanalog multiplexer 652 with addresses corresponding to the channels ofthe signal receiving lines 626, specifically, 32 circuit channels, tothereby sequentially change-over the received signals.

The address indicative of the position of the sensing matrix can begenerated by the channel switching logic 643 on the signal sending sideand the channel switching logic 654 on the signal receiving side. Asequence control circuit shown in FIG. 28 generates the address on thebasis of the signals from the respective channel switching logic units,and it writes the address of the position (the position of the sensingmatrix) where the metal ball has been detected, into a bidirectionalRAM. That is, the sequence control circuit serves as address generationmeans.

As shown in FIG. 28, the CPU memory control board 72 is furnished on thesignal sending side thereof with a CPU connector 662 which is connectedto a CPU (not shown), the sequence control circuit 663 which producessignal sending clock pulses in response to a start signal appliedthrough the CPU connector 662 by the CPU, a band-pass filter 664 whichaccepts the signal sending clock pulses and delivers signals to-be-sent,and an amplifier 665 which amplifies the signals to-be-sent and deliversthe amplified signals to the signal sending connector. The sequencecontrol circuit 663 is constructed so as to be capable of switchinglyproducing at least two signal sending frequencies; f₁ (for example, 1[MHz]) and f₂ (for example, 1.3 [MHz]).

The arrangement of the band-pass filter 664 is shown in FIG. 41.Referring to FIG. 41, the band-pass filter 664 includes a firstcapacitor 981 (C1) on the input side thereof, a first resistor 982 (R1),and a transformer 983 with a trimmer. Besides, the primary side of thetransformer 983 with the trimmer includes a second capacitor 984 (C2),while the secondary side thereof includes a third capacitor 985 (C3), asecond resistor 986 (R2) and a third resistor 987 (R3). In order to copewith the two or more signal-sending frequencies f₁ (1 MHz) and f₂ (1.3MHz), the transformer 983 with the trimmer is designed so as to resonatewith the intermediate frequency f₀ (for example, 1.1 [MHz]) between thesignal sending frequencies (refer to FIG. 42). The band-pass filter 664is one which passes the frequencies f₁ (for example, 1 MHz) and f₂ (forexample, 1.3 MHz).

In addition, the CPU memory control board 72 is furnished on the signalreceiving side thereof with an amplifier 671 which amplifies receivedsignals from the signal receiving connector 655, a band-pass filter 672which accepts the amplified signals, a full-wave rectifier/amplifier 673which accepts the received signals from the band-pass filter 672, twostages of low-pass filters 674a and 674b which accept the receivedsignals from the full-wave rectifier/amplifier 673, an A/D converter 675which accepts the received signals from the low-pass filter 674b anddelivers digital data to the bidirectional RAM 676 under the control ofthe sequence control circuit 663, and the bidirectional RAM 676 whichaccepts the digital data, writes the received data under the control ofthe sequence control circuit 663 and delivers the received data to theCPU through the CPU connector 662 in response to a read signal from thisCPU connector 662.

The full-wave rectifier/amplifier 673 is a circuit by which the signalfrom the signal receiving circuit is subjected to the full-waverectification. The two stages of low-pass filters 674a, 674b form anaveraging circuit by which the signal after the rectification by thefull-wave rectifier/amplifier 673 is subjected to averaging processing.

The full-wave rectifier/amplifier 673 and the two stages of low-passfilters 674a, 674b constitute a signal processing circuit for rectifyingand smoothing the received signal.

In the presence of the metal body, the bidirectional RAM 676 stores theaddress thereof on the basis of the appointment of the address of thesensing matrix from the sequence control circuit 663.

Further, the CPU memory control board 72 is furnished with a powersource unit 677.

The CPU is data processing means, which loads the data of the monitorpoints in the RAM card 73 being the memory for these monitor points andwhich also loads the coordinate position data (the addresses of thesensing matrix) in the bidirectional RAM 676 being the memory for themetal positions. Subsequently, the CPU checks the coordinate positiondata with the data of the monitor points, thereby judging if the metalbodies have reached the specified monitor positions (for example, thesafe holes and the out hole) on the panel.

As shown in FIG. 8, a continuous sinusoidal wave 81 which has afrequency of 1-1.3 MHz and which centers at 0 V is suitable as a voltagewaveform to be applied to the signal sending lines 622.

The game machines 10 develop noise at various frequencies, dependingupon the types thereof. When the frequency of the noise is identicalwith or close to the frequency of the signals sent to the sensing matrix620, the accuracy of detection of the metal body deterioratesdrastically. Accordingly, several sorts of metal detection apparatuseswhose signal sending frequencies are not identical with or close to thefrequencies of the noise in the frequency band of 1-1.3 MHz are preparedbeforehand in accordance with the types of the game machines 10, and themetal detection apparatus of the appropriate signal sending frequency isselected and mounted in conformity with the game machine 10to-be-installed. According to this expedient, the detection accuracy forthe metal body can be raised by eliminating the influence of the noiseat a low cost of fabrication. Moreover, when the metal detectionapparatus of the sort most suited to the game machine 10 is selected inadvance, the application thereof to the game machine 10 is facilitated.

Address signals and control signals from the CPU are transmitted to thegame machine 10 via the CPU connector 662 in the same manner as in thefirst embodiment.

In the game machine 10, on the signal sending side, the sequence controlcircuit 663 accepts the start signal and divides the frequency of acrystal oscillation clock at a value of 16 MHz as is needed, therebydelivering the signal sending clock. In the sequence control circuit663, at least two sorts of signal sending clock pulses can be selectedby a switch. Alternatively, it is possible to decide the frequency ofthe noise by noise detection means and to alter the frequency byfrequency switching means as will be stated later. Of the two or moresorts of clock pulses, one is selected and delivered as the signalsending clock so as not to be affected by the noise of the game machine10. That is, the frequencies f₁ (1 MHz) and f₂ (1.3 MHz) can bechanged-over by the switch. Thus, when the sending frequency of the sentsignals is identical with or close to the frequency of the noisedeveloped in the game machine 10 or the like, the sensing operation canbe rendered insusceptible to the noise.

The signal sending clock from the sequence control circuit 663 issubjected to waveshaping from the digital signal into the analog signalby the band-pass filter 664.

The band-pass filter 664 is capable of processing the two sorts ofsending signals of different frequencies. The first capacitor 981 (C1)on the input side cuts off the D.C. component of the sending signalbased on the digital signal. The input and output impedances of thefilter are adjusted with the first resistor 982 (R1), second resistor986 (R2) and third resistor 987 (R3). The transformer is tuned to thesignal sending frequency by the second capacitor 984 (C2), and the thirdcapacitor 985 (C3) on the secondary side. As illustrated in FIG. 42, theresonance point of the transformer is adjusted with the trimmer so as toequalize the magnitudes of the sending signals of the frequencies f₁ (1MHz) and f₂ (1.3 MHz). In this way, the sinusoidal waveform having thesame frequency as that of the digital signal can be produced by theband-pass filter 664. Moreover, even when the signal sending frequencyis altered, the filter can resonate with and deliver the new frequency.

After the waveshaping by the band-pass filter 664, the sending signal isamplified by the amplifier 665 and is delivered to the signal sendingconnector 641.

Further, the sending signal is amplified by the amplifier 642 in thesignal sending circuit 640. The analog multiplexer 644 changes-over thechannels by means of the channel switching logic 643. That is, thechannel switching logic 643 corresponds to the signal-sending-line rowcounter 45 depicted in FIG. 6, and the analog multiplexer 644 to thedecoder 42.

The totem-pole drivers 645 are sequentially operated in accordance withthe appointments from the analog multiplexer 644. Thus, the totem-poledrivers 645 deliver the signals amplified by the amplifier 642, to thesignal sending lines 622 sequentially at predetermined cycles (refer toa step 691 in FIG. 29).

On the signal receiving side, as indicated in FIG. 27, currents beingelectromagnetic characteristic values which appear on the plurality ofsignal receiving lines 626 are amplified by 10 times by means of the CTsensors 651. Since the CT sensors 651 are employed for theamplification, the gain of the amplifier on the signal receiving sideneed not be heightened accordingly. Since the amplification by the CTsensors 651 proceeds with the corresponding signal receiving lines 626isolated from the analog multiplexer 652, it can be effected withoutdeveloping noise. Thus, in contrast to a case of employing OP(operational) amplifiers, this embodiment can prevent the occurrences ofnoise and D.C. drifts ascribable to the OP amplifiers themselves, andthe accuracy of detection for the received signals can be enhanced. Theadoption of the CT sensors 651 dispenses with the use of the OPamplifiers being usually larger in size than the CT sensors, and permitsreduction in the size of the matrix I/O sending/receiving board 71.

The analog multiplexer 652 is the circuit in which the signals acceptedfrom the individual signal receiving lines 626 via the CT sensors 651are changed-over in accordance with the channel switching logic 654 andthen delivered sequentially at predetermined cycles. That is, itchanges-over the 32 signal receiving lines 626 at the fixed cycles andmultiplexes the received signals.

The signals from the analog multiplexer 652 are amplified by 100 timesby means of the amplifier 653 (refer to a step 692 in FIG. 29).

As illustrated in FIG. 28, each of the received signals is amplified anddetected via the signal receiving connector 655, amplifier 671 andband-pass filter 672.

The received signal from the band-pass filter 672 is subjected to therectification processing and the averaging processing without performinga sample holding operation or a peak holding operation.

The reason why neither the sample holding operation nor the peak holdingoperation is performed, is that disadvantages to be stated below areinvolved in these operations.

In case of performing the sample holding operation, the signal isprocessed at any desired one of sampling points S₁ -S₄ indicated in FIG.38, (A). Therefore, in a case where the signal is sampled at the pointS₂ by way of example, there is the disadvantage that the peak of thewaveform is difficult to catch as illustrated in FIG. 38, (B). At thestage succeeding the rectifier circuit, the signal is digitized by theA/D converter for the purpose of detecting whether or not the metal ballexists. Accordingly, the signal must be held at a value which exceedsthe threshold voltage of the A/D converter. More specifically, in theabsence of the metal ball, substantially the same received signal as thesignal given by the sent signal can be obtained, but in the presence ofthe metal ball, the amplitude of the received signal diminishes due tothe metal ball. This is objectionable because the presence or absence ofthe metal ball is detected on the basis of the difference of theamplitudes of the received signals.

On the other hand, in case of performing the peak holding operation, apeak indicated at P₁ in FIG. 39, (A) is caught, and the signal isprocessed as illustrated in FIG. 39, (B), so that the peak of thewaveform can really be caught. However, such a method wherein the dataof an instantaneous value is caught and processed has the disadvantageof lacking stability, because the desired point of the peak holdingoperation fluctuates due to a slight change in any adjusted partattributed to a temperature drift or the like. This disadvantagesimilarly applies to the case of the sample holding operation.

Further, in a case where the signal contains noise as shown in FIG. 40,the noise is caught as the signal as shown in FIG. 40, (B) when itdevelops at the moment of the catch of the signal. It is accordinglyapprehended to erroneously detect the peak value and to misrecognize thepresence of the metal ball. This similarly applies to the case of thesample holding operation.

For the above reasons, in this embodiment, the received signal issubjected to the rectification processing and the averaging processingwithout carrying out the sample holding operation or the peak holdingoperation.

In this embodiment, as shown in FIG. 30A, the received signal from theband-pass filter 672 is an analog signal which has several cycles as onescan. The analog signal is waveshaped as shown in FIG. 30B by thefull-wave rectifier/amplifier 673. Alternatively, the full-waverectifier/amplifier 673 may well be replaced with a half-waverectifier/amplifier.

The signal from the full-wave rectifier/amplifier 673 is averaged byintegration processing as shown in FIG. 30C by means of the low-passfilter 674a, and the resulting signal is further averaged as shown inFIG. 30D by means of the low-pass filter 674b. Thus, noise is alsoaveraged together with the received signal. Since, however, themagnitude of the noise is very slight as compared with that of thesignal, an error ascribable to the noise is negligible. Thus, the peakvalue can be detected without catching the noise as the signal. Thereason therefor is that, in averaging the received signal by means ofthe low-pass filters 674a and 674b, this signal has already passedthrough the band-pass filter 672, so noise intense enough to incur an,appreciable error is not involved. For the purpose of avoiding theerror, the signal sending frequency is selected to be the frequencywhich is not affected by the noise of the game machine 10, and a filtersuited to the signal sending frequency is employed as the bandpassfilter 672.

Subsequently, the received signal is delivered to the A/D converter 675.This A/D converter 675 is supplied with the received signal through thefull-wave rectifier/amplifier 673, low-pass filter 674a and low-passfilter 674b. In the A/D converter 675, the presence or absence of themetal ball is converted into the digital signal in accordance with thethreshold voltage, so as to record the received data in thebidirectional RAM 676 under the control of the sequence control circuit676 (refer to a step 693 in FIG. 29). The speed of this processing is ashigh as 25000 times per second. After the bidirectional RAM 676 hasrecorded the received data irrespective of the operation of the CPU 30in response to a write signal delivered from the sequence controlcircuit 676, it increments the address by one upon inputting one clockpulse (refer to a step 694 in FIG. 29). The capacity of thebidirectional RAM 676 is, for example, 2048 bytes.

In this way, the analog multiplexer 652 of the signal receiving circuit650 changes-over the signals from the individual signal receiving lines626 (refer to a step 695 in FIG. 29) until the above steps are repeated32 times in correspondence with the 32 signal receiving lines 626 (referto a step 696 in FIG. 29). After the steps have been repeated 32 times,the analog multiplexer 644 of the signal sending circuit 640changes-over the signal sending lines 622 (refer to a step 697 in FIG.29), whereupon the signal processing is repeated again.

Thus, the bidirectional RAM 676 stores therein the positions of themetal balls in the sensing matrix as the coordinate data of the signalsending lines 622 and signal receiving lines 626, on the basis of thesignals from the signal receiving circuit 650 and in terms of theintersecting positions between the signal receiving lines 626 of thechanged received signals and the corresponding signal sending lines 622having sent the signals.

In the case where the option card 74 is utilized due to an increaseddata quantity, the data of the bidirectional RAM 676 can be recorded inthis option card 74. The data recorded in the option card 74 can beprocessed by another personal computer connected to this option card.

Besides, the RAM card 173 stores therein the data of the monitor pointsfor the metal balls, and the CPU loads the address data stored in theRAM card 173, the address data being indicative of the positions of thesensing units 620a, 620a, . . . which correspond to the essential placesof the safe holes 14a, 14a, . . . , projected-ball detection positionand out hole 15.

The CPU issues the read start signal when it is needed so as to read outand arithmetically process the data on the positions of the metal bodiesrecorded in the bidirectional RAM 676, and to check the coordinate datawith the data of the monitor points, thereby monitoring the metal balls.That is, the CPU does not derive the coordinate data directly from thesignal receiving circuit 650, but it temporarily loads the coordinatedata recorded in the bidirectional RAM 676.

In addition, the CPU repeats this processing. The CPU and the circuitsof the CPU memory control board 72 execute the processing whileneglecting wait times for each other, so that the burden of the CPU 30can be relieved to heighten the processing speed of this CPU 30. The CPU30 follows up the motions of the metal bodies on the panel 11 of thegame machine 10, such as the situation of hits, in the form of changesin coordinate values, thereby monitoring the progress of a game. Herein,the CPU 30 counts the hit balls, premium balls, projected balls, etc.,making it possible to manage the end of the game or check anyabnormality ascribable to an unfair practice, or to utilize the recordeddata for pin adjustments, etc., depending upon circumstances.

When monitoring the situation of the metal balls in the game machine 10of a new type, the RAM card 173 can have its information rewritten or beexchanged in conformity with the type. The RAM card 173 permits thepositional data of the monitor points to be read out of the CPU 30merely by setting it in the interface portion 76, and it is easy toalter the data of the monitor points even when it is to be applied to alarge number of types of game machines for reasons of replacement of thegame machines, or the like. In writing data into the RAM card 173, thedata can be input by connecting this RAM card to another personalcomputer through the interface portion of the latter. As long as thegame machines of the same type are concerned, the RAM cards 173 can befabricated by copying a single card. Moreover, the RAM card 173 isversatile, so that when more complicated processing is to be executed,it can be coped with by selecting the CPU at will.

Incidentally, regarding the CPU 30, when the algorithm for detecting theball is simple, the use of an inexpensive 8-bit CPU suffices, and whenthe required algorithm is complicated, a 16-bit CPU may well be selectedfor executing high-speed processing. In either case, the rate of thescanning of the metal body is not affected by the CPU because the CPU isnot concerned in the scanning.

In this manner, in the case where the current is caused to flow throughthe signal sending line 622 in the folded-back shape so as to generate amagnetic field and where an electromotive force is generated by themutual induction in the signal receiving line 626 which iselectromagnetically coupled with the signal sending line 622, an eddycurrent is produced in the surface of the metal body and in thedirection of canceling a magnetic flux based on the sensing matrix 620when the metal body comes near the sensing unit 620a. Then, themagnitude of an induced current appearing in the signal receiving line626 changes at the pertinent position. The signal sending lines 622,622, . . . and the signal receiving lines 626, 626, . . . correspondingthereto on such occasions can be detected by the scanning operations asstated above.

Accordingly, the positions of the metal bodies can be grasped as thecoordinates of the positions where the signal receiving lines 626, 626,. . . whose impedances have changed intersect with the associated signalsending lines 622, 622, . . . The total number of the sensing units 620ais 1024 in conformity with the signal sending lines 622 in the 32 rowsand the signal receiving lines 626 in the 32 columns. Therefore, nomatter which of the safe holes 14a and the out hole 15 in the panel 611the metal body may pass through, it can be detected.

Incidentally, since the voltage waveform 81 for the signal sending lines622 is the continuous sinusoidal wave centering at 0 V, noise as in thecase of a square wave does not develop, and detrimental effects on theother devices such as the CPU can be prevented.

Moreover, since the voltage waveform 81 is at 1-1.3 MHz in terms of thesignal sending frequency band, it can heighten a reaction sensitivitybesides being less susceptible to the noise arriving from the peripheralequipment of the game machine 10. Incidentally, the components capableof processing the signals in the frequency band of 1-1.3 MHz are lessexpensive than components for processing signals in a higher frequencyband. In addition, the signal detection apparatus at the signal sendingfrequency which is not identical with or close to the frequency of thenoise of the game machine 10 is selected in accordance with the type ofthis game machine, so that a favorable detection accuracy for the metalbody can be attained without being affected by the noise.

Further, the inner protective glass plate 617a and the outer glass plate617c protect the signal sending lines 622 and the signal receiving lines626 from physical damage ascribable to shocks etc., from dust, and fromcorrosion ascribable to oxidation etc., so that the durability of thesensing matrix 620 can be enhanced to prolong the lifetime thereof.

Still further, the transparent conductor film 28 on the front surface ofthe outer glass plate 617d shields the sensing matrix against theexternal electrical influences of metals and dielectrics, and it alsofunctions to heighten the reaction sensitivity to the metal body.

The CPU 30 reads out the data items recorded in the RAM card 73 inrelation to the positions of the sensing units 620a, 620a, . . .corresponding to the essential places such as the safe holes 14a, 14a, .. . and the out hole 15, and it follows up the motions of the metalbodies on the panel of the game machine, such as the situation of hits,in the form of changes in coordinate values, thereby monitoring theprogress of the game. Herein, depending upon circumstances, it ispossible to manage the end of the game or check any abnormalityascribable to unfair practice, or to utilize the recorded data for pinadjustments, etc.

When the metal bodies entering the safe holes is to be monitored in thegame machine 10 of the new type, the RAM card 73 may be exchanged inconformity with the type.

Incidentally, since the signal sending terminals 623 and signalreceiving terminals 627 are located on the lower side of the gamemachine and are respectively connected with the signal sending connector67a and signal receiving connector 67b at the inner lower part of themounting frame, the connections can be reliably effected by utilizingthe weight of the inner glass element (front glass) 617. Moreover, inattaching the inner glass element 617 to the mounting frame, theconnections can be simultaneously done.

Regarding the exchange and mounting of the inner glass element 617provided with the sensing matrix 620, the signal sending connector 67aand signal receiving connector 67b are detachable, and the inner glasselement 617 is readily detached from the signal sending circuit 640 andsignal receiving circuit 650 of the mounting frame, so that the sensingmatrix 620 having become out of order can be easily exchanged. Also, thesensing matrix 620 can be easily installed on a game machine of the typein which this sensing matrix 620 is not packaged.

It is also allowed to locate the signal sending connector 67a and signalreceiving connector 67b at the inner upper part of the mounting frame,and to dispose the signal sending terminals 23 and signal receivingterminals 27 on the upper side of the game machine. In this case, it ispossible to render the signal sending circuit board 766a, signalreceiving circuit board 766b, signal sending connector 67a and signalreceiving connector 67b inoffensive to the eye.

In addition, the signal sending lines 622 and signal receiving lines 626are made of the wire pieces 62, and the turning portions 61 andcircumventive portions 64 thereof are formed of the conductor patterns.Therefore, when the wire 62 for detecting the "pachinko" ball is finallyformed, the detection portion for the "pachinko" ball does not impedethe view of the panel 11 of the "pachinko" game machine 10 and does notoffend the game player's eye.

The twelfth embodiment of the present invention is described below.

FIGS. 31-33 illustrate the twelfth embodiment of the present invention.This embodiment is the same as the eleventh embodiment except for theconnections of signal sending terminals with a signal sending circuitand signal receiving terminals with a signal receiving circuit. The sameconstituents as those of the eleventh embodiment have the same symbolsassigned thereto, and shall not be repeatedly explained.

As shown in FIG. 31, a signal sending circuit board 766a and a signalreceiving circuit board 766b are disposed at the inner lower part 765 ofa mounting frame, and a signal sending connector 67a and a signalreceiving connector 67b are respectively provided thereon at positionscorresponding to the signal sending terminals 723 and the signalreceiving terminals 727.

The signal sending connector 67a is a rubber connector for detachablyconnecting the signal sending terminals 723 to the signal sendingcircuit, while the signal receiving connector 67b is a rubber connectorfor detachably connecting the signal receiving terminals 727 to thesignal receiving circuit. More specifically, the signal sendingconnector 67a or signal receiving connector 67b is so constructed that alarge number of connection leads 69 are wound round an elongateinsulator member 68 extending along the signal sending circuit board766a or signal receiving circuit board 766b. The connection leads 69 areconnected to the signal sending terminals 723 and the correspondingterminals of the signal sending circuit or the signal receivingterminals 727 and the corresponding terminals of the signal receivingcircuit in one-to-one or more-to-one correspondence, preferably in fiveor so-to-one correspondence.

The signal sending terminals 723 and the signal receiving terminals 727are arranged on the edge of the lower end 617p of the inner glasselement 617. As shown in FIGS. 32 and 33, the terminals are furtheroverlaid with terminal fixtures 720aeach of which holds the edge of thelower end 617p of the inner glass element 617 between both the innersurfaces thereof.

The signal sending terminals 723 and signal receiving terminals 727 arerespectively connected with the signal sending circuit and signalreceiving circuit as follows: As shown in FIG. 33, the signal sendingterminals 723 and signal receiving terminals 727 are positioned underthe inner glass element 617 so as to be connectible with the signalsending connector 67a and signal receiving connector 67b, and theresulting inner glass element 617 is fitted in the mounting frame sothat the signal sending terminals 723 and signal receiving terminals 727lying on the edge of the inner glass element 617 may be touched andconnected with the upper parts of the signal sending connector 67a andsignal receiving connector 67b by the weight of the element 617 which isabout 1.2 kg.

Now, the thirteenth embodiment of the present invention will bedescribed.

This embodiment is the same as the eleventh embodiment except that aninner glass element is constructed by stacking the three layers of aninner protective glass plate, a glass base plate and an outer glassplate. The same constituents as those of the eleventh embodiment havethe same symbols assigned thereto, and shall not be repeatedlyexplained.

FIG. 34 shows the structure of the inner glass element which bears asensing matrix in the thirteenth embodiment. More specifically, theinner glass element 617 is constructed of the three stacked layers ofthe inner protective glass plate 617a, glass base plate 887 and outerglass plate 617c. A plurality of signal receiving lines 626 ofparalleled folded-back shape are formed on one surface of the glass baseplate 887 and have the inner protective glass plate 617a stuck thereon,while a plurality of signal sending lines 622 of paralleled folded-backshape are formed on the opposite surface of the glass base plate 887 andhave the outer protective glass plate 617c stuck thereon.

Alternatively, in the pattern processing of the signal sending lines 622and signal receiving lines 626, these lines may well be respectivelyformed on the surfaces of the inner protective glass plate 617a andouter glass plate 617c, not on both the surfaces of the glass base plate887.

Besides, the glass base plate 887 made of glass may well be substitutedby a plastic film.

Now, the fourteenth embodiment of the present invention will bedescribed.

This embodiment has the same construction as that of the eleventhembodiment except that each circumventing circuit board is formed withcircumventive portions on both the surfaces thereof. The sameconstituents as those of the eleventh embodiment have the same symbolsassigned thereto, and shall not be repeatedly explained.

As shown in FIG. 35, a signal-sending-side glass base plate 617c in asquare shape is such that a signal-sending-side turning circuit board719a made of an elongate flexible printed-wiring circuit board (FPC) isbonded so as to extend along one vertical latus of this base plate 617c,and that the signal-sending-side circumventing circuit board 719 in aletter-L shape is bonded so as to extend along the opposite verticallatus of this base plate 617c and part of the bottom latus thereof. Asdepicted in FIG. 22, a plurality of signal sending terminals 623,specifically 64 of them, which are similarly made using a flexibleprinted-wiring circuit board, and which extend vertically for externalconnections are formed at the lower end of the signal-sending-sidecircumventing circuit board 719 and along part of the lower-end latusthereof.

The circumventive portions 64 leading to the corresponding signalsending terminals 623 are extended to these signal sending terminals 623while lying on both the surfaces of the signal-sending-sidecircumventing circuit board 719 alternately. Among such circumventiveportions 64, those which lie on the rear side of the signal-sending-sidecircumventing circuit board 719, that is, on the side thereofconfronting the signal-sending-side glass base plate 617c have theirstart points 64a connected to the front side of the signal-sending-sidecircumventing circuit board 719 by through holes 720 which are formed inthe corresponding positions of the circuit board 719. While beingtensed, each wire piece 62 extending from the end 61a of a correspondingturning portion has its other end 62b connected to the start point 64aof the circumventive portion 64 on the terminal side by welding orsoldering with a solder 63.

In this embodiment, the width of the circumventive portions extending inthe vertical direction of the glass base plate can be easily set assmall as, for example, about 10 mm or less.

Incidentally, similarly to the signal-sending-side circumventing circuitboard 719, the signal-receiving-side circumventing circuit board of asignal-receiving-side glass base plate can be formed with the alternatecircumventive portions on both its surfaces by providing through holestherein.

In order to make the width of the circumventive portions small, astructure in which a plurality of circumventing circuit boards arestacked may well be adopted instead of the above structure in which thecircumventive portions are disposed on both the surfaces of thecircumventing circuit board.

Now, the fifteenth embodiment of the present invention will bedescribed. This embodiment is an example of a metal detection apparatuswhich has a measure against noise. The noise reduction measure adoptedin this embodiment can be applied to various aspects in the presentinvention, for example, the foregoing embodiments.

As shown in FIG. 36, the metal detection apparatus in this embodimentincludes noise detection means 1035 and noise level measurement means1036, and signal sending interrupt means 1037 and frequency switchingmeans 1038 which are included in a CPU 1030.

The noise detection means 1035 is means for accepting a signal receivedby a signal receiving circuit 1050, and for delivering a noise signalwhen the noise of the accepted signal has been detected. The noise levelmeasurement means 1036 is means connected to the noise detection means1035, for measuring the levels of the detected noise of the noisedetection means 1035 at respective frequencies. Herein, by way ofexample, the levels may be measured for specified frequency componentsset in advance or may well be measured for the respective frequenciesobtained by the frequency analysis of the noise.

The signal sending interrupt means 1037 and the frequency switchingmeans 1038 are respectively formed by running specified programs in theCPU 1030. The signal sending interrupt means 1037 is means for stoppingthe delivery of a signal sending clock from a sequence control circuit47 in accordance with the noise signal from the noise detection means1035, thereby to interrupting the signal sending operation of a signalsending circuit 1040. The frequency switching means 1038 is means forchanging-over the frequency of the sending signal of the signal sendingcircuit 1040 to a frequency which is not susceptible to the detectednoise, on the basis of the measured result of the noise levelmeasurement means 1036. The change-over to the frequency which is notsusceptible to the noise is effected between, for example, the twopreset frequencies of 1 MHz and 1.3 MHz. Incidentally, the frequenciescan be changed-over, not only by the program, but also by hardware.

When the noise is contained in the received signal of the signalreceiving circuit 1050, the noise detection means 1035 detects thisnoise. The signal sending interrupt means 1037 interrupts the signalsending operation of the signal sending circuit 1040 in accordance withthe noise signal from the noise detection means 1035. The noise levelmeasurement means 1036 measures the levels of the respective frequenciesof the noise detected by the noise detection means 1035. 0n the basis ofthe measured result, the frequency switching means 1038 changes-over thefrequency of the sending signal of the signal sending circuit 1040 tothe frequency which is not susceptible to the detected noise, betweenthe two preset frequencies of 1 [MHz] and 1.3 [MHz]. In this way, afavorable accuracy of detection for the "pachinko" ball can be attainedwithout being influenced by the noise.

According to such a construction, various types of machines whichdevelop noise of different frequencies can be coped with by the singlesort of metal detection apparatus.

In this embodiment, the frequency switching means 1038 may well utilizea system in which the sending signal frequency is changed-over to anydesired frequency by the use of a PLL (phase-locked loop), instead ofthe system in which either of the two frequencies is selected.

The sixteenth embodiment of the present invention is described below.This embodiment consists in comprising a signal receiving circuit inwhich means for detecting a current induced in each signal receivingline is altered.

This embodiment is the same as the embodiment shown in FIG. 27, exceptthat the CT sensors are replaced with amplifiers.

As shown in FIG. 37, in the signal receiving circuit, the amplifiers of32 circuit channels 1151 are respectively connected on the sides of thesignal receiving lines of 32 circuit channels 26. The amplifiers 1151amplify signals from the signal receiving lines 26, and deliver theamplified signals to an analog multiplexer. In this manner, the signalreceiving circuit can be configured by substituting the amplifiers 1151for the CT sensors.

The seventeenth embodiment of the present invention is described below.In this embodiment, a construction for sensing the presence of a gameplayer will be explained with reference to FIGS. 43 and 45.

As shown in FIG. 45, a game player sensor 80 for sensing the presence ofa game player is encased in the front of a game machine. The setup ofthe game player sensor 80 is shown in FIG. 43. Referring to FIG. 43, thegame player sensor 80 includes an oscillation circuit 1281 for emittingan infrared beam, an output control 1282 for a beam transmission signal,a beam transmitter 1283, a beam receiver 1284, a received beam amplifier1285, and a received beam discriminator 1286. The beam transmitter 1283and the beam receiver 1284 are so arranged that, when there is a gameplayer at a playing position for the game machine, the infrared beamtransmitted from the beam transmitter 1283 is reflected by the gameplayer, whereupon the reflected beam is received by the beam receiver1284. The beam transmission signal output control 1282 is a gatecircuit, through which a beam transmission signal from the oscillationcircuit 1281 is passed. Thus, the beam transmission signal is output fora time period during which the gate circuit is enabled. While the gatecircuit is disabled, the beam transmission signal is not output. Thegating may be at fixed periods, or may well be at random periods. Asignal for the gating is applied also to the received beam amplifier1285 so as to supply the output of the beam receiver 1284 thereto foronly the time period during which the gate circuit is enabled, wherebythe detrimental effects of noise can be relieved. The signal to betransmitted from the beam transmitter 1283 may well be anelectromagnetic or ultrasonic wave instead of the infrared signal. Inthe received beam discriminator 1286, the received signal amplified bythe received beam amplifier 1285 is recognized, and the presence of thegame player is discriminated subject to the reflected signal. The gameplayer sensor 80 can alternatively be mounted on the matrix I/O board 71shown in FIG. 24 or FIG. 45.

Referring to. FIG. 43, the oscillation circuit 1281 emits the infraredbeam, which is delivered by the gate circuit of the beam transmissionsignal output control 1282 while this gate circuit is enabled. The beamtransmitter 1283 is driven by the emitted signal, thereby transmittingthe infrared beam. In the absence of a game player, the transmittedinfrared beam is not reflected, and hence, no signal is received by thebeam receiver 1284. In the presence of a game player, the transmittedinfrared beam is reflected, and the reflected beam is received by thebeam receiver 1284. The received signal of the beam receiver 1284 isamplified by the received beam amplifier 1285 while the gate circuit isenabled. The received beam discriminator 1286 recognizes the amplifiedreceived signal, and decides the presence of a game player.Incidentally, considering a time period which is taken since thetransmission of the infrared beam from the beam transmitter 1283 tillthe reception of the reflected beam, the gating signal of the beamreceiving side may well be delayed for the time period.

Further, the number of game players in the whole game parlor can begrasped in such a way that signals from the received beam discriminators1286 are collected from all the game machines and are managed.

Alternatively, the beam transmitter 1283 and the beam receiver 1284 canbe disposed at separate positions. By way of example, it is alsopossible to install the beam transmitter 1283 at the upper part of thegame machine 10 so as to transmit the beam toward the position fromwhich a game player is to come, and to install the beam receiver 1284 atthe lower part of the game machine 10 at which the reflected beam can bereceived.

The eighteenth embodiment of the present invention is described below.In this embodiment, another construction for sensing a game player willbe explained with reference to FIG. 44.

As shown in FIG. 44, a game player sensor 80A for sensing the presenceof a game player is encased in the front of a game machine. The gameplayer sensor 80A has only the receiving portion of the game playersensor 80 stated before. FIG. 44 shows a front view of an island 2101which has the game machines 10 in this embodiment. More specifically,the plurality of game machines 10 are disposed at the front of theisland 2101, and each of them has a matrix I/O board 71. The game playersensor 80A can be provided in the matrix I/O board 71.

The game player sensor 80A includes the beam receiver 1284, the receivedbeam amplifier 1285 and the beam discriminator 1286. The beam receiver1284 can receive infrared radiation emitted by a person, whereby thepresence of a game player can be detected. Alternatively, the beamreceiver 1284 may well be replaced with a sensor which senses the bodytemperature of a person.

According to this embodiment, the game player sensor has only thereceiving portion and can therefore be reduced in size.

Incidentally, in each of the embodiments, the turning circuit boardsor/and the circumventing circuit boards may well be made of thin, glassepoxy circuit boards in lieu of the flexible printed-wiring circuitboards (FPC). Since the glass epoxy circuit board is opal in color, itis inoffensive to the eye when in use. Besides, since it is immune toheat, it is prevented from being thermally broken down when the wirepieces of the signal sending lines and signal receiving lines aresoldered.

The signal sending terminals and the signal receiving terminals can bebrought into the structure in which they are concentratedly arranged onthe lower end side in relation to the inner glass element (front glass)as mounted on the game machine. Of course, this structure is notrestrictive, but the terminals may well be concentratedly arranged onthe upper end side of the inner glass element. Thus, it is possible torender the signal sending connector, signal receiving connector, signalsending circuit board and signal receiving circuit board inoffensive tothe eye. Besides, in the case where the end parts of the signal sendinglines and those of the signal receiving lines are respectively locatedat one end of the base plate as the signal sending terminals and thesignal receiving terminals, the lines can be respectively connectedreliably with the signal sending connector and the signal receivingconnector by utilizing the weight of the base plate.

Besides, in each of the embodiments, the turning portions formed of theconductor patterns may well be replaced with ones in which the wirepieces of the signal sending lines and signal receiving lines aredirectly turned back and in which the turned-back parts are fixed with abinder.

As described above, according to the embodiments of the presentinvention, any position of existence of a metal body within a specifiedspace can be detected without actual contact with the metal body andwithout employing contacts which require a physical contact with themetal object. Thus, according to the present invention, various problemsattendant upon the provision of the contacts or the likes can be solved,and the durability and the reliability can be enhanced in the detectionof the metal body.

Especially, the present invention is well suited to the detection of theposition of existence of the metal body which is moving or remainsstationary within the specified space, particularly a space held betweenparallel planes. In, for example, a game machine, it is permitted toeasily and quickly obtain data items on the trajectories of the metalbodies on a panel, the number of the metal bodies struck by a gameplayer, the rate of the metal balls entering safe holes, etc., and thedetails of a game can be known in a remote place. Therefore, the levelof the attribute management of the game machine can be enhanced, andanybody can adjust the pins of the game machine with ease. Also, thedistribution of the metal bodies on the plane can be detected with ease.

INDUSTRIAL APPLICABILITY

The present invention is applicable to any of various equipments fordetecting the position of a metal body existent in a specified space. Byway of example, it is applicable to the detection of the trace of themetal body in a game machine in which this metal body is moved along apanel. Besides, the distribution of the positions of existence of themetal body can be detected by placing the metal body on a sensing matrixwhich constitutes the present invention. An apparatus for recognizingthe shape of the metal body itself can be constructed by utilizing theabove distribution of existence of the metal body. In addition, a systemfor managing goods can be built by utilizing information on thedistribution of existence of the metal bodies. Further, it is possibleto construct a sensor for inputting instructions etc. in such a way thatthe metal body is brought near to the desired positions of the sensingmatrix constituting the present invention.

We claim:
 1. An apparatus for detecting a moveable metal body in agaming machine comprising:a sensor including a folded signal sendingline including two lines connected at one end and which serves to carrya current for generating a magnetic field when energized; and a foldedsignal receiving line including two lines connected at one end which isarranged at a position permitting it to be electromagnetically coupledwith said folded signal sending line, and which serves to detect amagnetic flux change caused by the approach of metal, said folded signalsending line and said folded signal receiving line each being arrangedin separate parallel planes and in directions orthogonal to each other;said sensor being constructed as a sensing matrix in which a pluralityof folded signal sending lines are arranged coplanarly and a pluralityof folded signal receiving lines are arranged coplanarly; signal sendingmeans connected to the respective folded signal sending lines, forsuccessively sending signals of predetermined frequency to saidrespective folded signal sending lines; and, signal receiving meansconnected to the respective folded signal receiving lines, forsuccessively receiving the signals from said respective folded signalreceiving lines in synchronism with said folded signal sending meanswherein said signal sending means includes sending-signal switchingmeans for successively delivering signals-to-be-sent to said respectivefolded signal sending lines, said signal receiving means includesreceiving-signal switching means for successively acceptingsignals-to-be-received from said respective folding signal receivinglines, said signal receiving means includes decision means for judgingwhether or not said metal exists, from the signals of said folded signalreceiving lines, said sensing matrix is arranged in opposition to saidpanel with a space therebetween at least large enough to pass said metalbody, and said signal sending means and said signal receiving means areconnected to said sensing matrix, to detect the location of said metalbody.
 2. The apparatus of claim 1, characterized in that said signalreceiving means includes detection means for detecting induced currentsdeveloped on said folded signal receiving lines, and said folded signalreceiving lines are isolated.
 3. The apparatus of claim 2, characterizedin that said detection means is configured with current transformers. 4.The apparatus of claim 1, characterized in that said signal receivingmeans further includes a signal processing circuit for rectifying andsmoothing the received signals, at a stage preceding said decisionmeans.
 5. The apparatus of claim 1, further comprising addressgeneration means for evaluating an address which indicates a position ofsaid sensing matrix on the basis of said sending-signal switching meansand said receiving-signal switching means.
 6. The apparatus of claim 5,further comprising a user sensor located in front of said panel so as todetermine the presence of a user in front of said panel.
 7. Theapparatus of claim 5, further comprising record means for recording anaddress of a position of said sensing matrix at which said metal bodyexists.
 8. The apparatus of claim 7, further comprising monitor-positionrecord means for recording at least one specified monitor position onsaid panel, on the basis of said address of said sensing matrix.
 9. Theapparatus of claim 8, further comprising data processing means forcomparing positional information of said metal body detected in saidsensing matrix and positional information of said monitor-positionrecord means, thereby determining if said metal body has reached thespecified monitor position on said panel.
 10. The apparatus of claim 8,characterized by further comprising write means for writing specifiedpositional information of said matrix, into said monitor-position recordmeans.
 11. The apparatus of claim 8 further comprising write means forwriting specified positional information regarding said matrix, intosaid monitor-position record means, wherein said monitor-position recordmeans is detachable storage means.
 12. The apparatus of claim 1, furthercomprising noise detection means for detecting a noise component of asignal received by said signal receiving means, in order to deliver anoise detection signal as an output, and sending interrupt means forstopping the signal sending operation of said signal sending means inaccordance with the noise detection signal from said noise detectionmeans.
 13. The apparatus of claim 12 further comprising noise levelmeasurement means for measuring a level of the detected noise at eachfrequency; and frequency switching means for changing-over the frequencyof a signal to-be-sent by said signal sending means to a frequency notaffected by the detected noise, on the basis of a measured result of thenoise level detection means.
 14. The apparatus of claim 13 furthercomprising a band-pass filter by which said frequency of the signalto-be-sent of said signal sending means and said frequency not affectedby said detected noise are passed in said signal sending operation. 15.An apparatus as defined in claim 1, wherein said signal sending meansincludes scanning means for sending the signals to said plurality ofsignal sending lines in succession, and said signal receiving meansincludes scanning means for selecting said plurality of signal receivinglines in succession.